HIGH-Tc UPDATE E-MAIL VERSION, VOL. 13, NO. 24, Dec. 15, 1999.
<p>
 Published at Iowa State University. Funded by ARPA, and other
 agencies, organizations, and individuals.
 <hr>
<p>
 The e-mail version of the High-Tc Update is sent to e-mail addresses
 accessible over INTERNET addresses. You can send e-mail messages to the
 editor at <a href="mailto:MITRA@AMESLAB.GOV">MITRA@AMESLAB.GOV</a> or <a href="mailto:MITRA@IASTATE.EDU">MITRA@IASTATE.EDU.</a>
<p>
 The High-Tc Update web page is located at the URL
 <a href="http://www.iitap.iastate.edu/htcu/htcu.html">http://www.iitap.iastate.edu/htcu/htcu.html</a>
<p>
 PLEASE NOTE: Issues of High-Tc Update can be sent as an e-mail
 attachment (a Microsoft Word or PDF version). These versions preserve
 the Greek letters, special characters, accents, etc. The PDF version
 looks exactly like the hard copy (no longer available) with the two-
 column format and graphics. If you are interested in the the either of
 the alternate formats instead of the ASCII text version, please contact
 the editor.
<p>
 <hr>
<p>
 PLEASE READ: The electronic-mail version of High-Tc Update is generated
 from a Macintosh Microsoft Word file and turned into a text file that
 can be transferred electronically. Formatting commands, Greek symbols,
 diacritical marks, etc. are lost in this transformation. In order to
 improve the readability of the e-mail version, the newsletter staff add
 explanatory marks as needed to the text file. For example, a carat
 (10^5) indicates a superscript (ten to the fifth). A carat followed by
 a bracket (cm^[-2]) indicates everything within the brackets is
 superscripted (centimeter to the minus 2). A bracket followed by a
 carat ([18]^O) indicates everything before the carat is superscripted.
 An underline (M_i) indicates a subscript (M subscript i). Most Greek
 letters are spelled out (Delta, mu, tau, pi, Omega), although delta is
 left as "d." In most instances, easily recognizable formulas or units
 are left as they appear: Tc, Jc, YBa2Cu3O7, O2. Mu-m is changed to
 micrometers. Diacritical marks (accents, tildes, carats, etc.) are
 removed, but the German umlaut (e.g., a, o, or u with two dots over it)
 is changed into a, o, or u followed by e. If needed for clarity,
 hyphens are occasionally inserted between spelled-out Greek letters or
 symbols (ohm-cm, sin-theta).
 <hr>
<p>
 NOTA BENE:
<p>
 Vortex dynamics
<p>
 As noted in a preprint by Y. Paltiel (Weizmann Institute) et al., recent
 studies of the vortex lattice in type-II superconductors have shown a
 number of puzzling phenomena including (a) low-frequency noise, (b) slow
 voltage oscillations, (c) history-dependent dynamic response, (d) memory
 of the direction, amplitude, duration, and even the frequency of the
 previously applied current, (e) high vortex mobility for ac current with
 no apparent vortex motion at dc current, and (f) strong suppression of
 an ac response by a small dc bias. The authors used an array of 19 2D-
 electron-gas (2DEG) Hall sensors, each of size 10 micrometers x 10
 micrometers, to determine the current distribution across single
 crystals of 2H-NbSe2 under various dc bias conditions and ac currents.
 The results revealed a generic mechanism that accounts for the above
 puzzling observations in terms of a competition between the injection of
 a disordered vortex phase at the sample edges, and the dynamic annealing
 of this metastable disorder by the transport current. For an ac
 current, only narrow regions near the edges are in the disordered phase,
 while for dc bias, most of the sample is filled by the pinned disorder,
 preventing vortex motion. The resulting spatial profile of vortex-
 lattice disorder acts as an active memory of the previous history.
<p>
 Investigations have been carried out by A. P. Rassau (Southampton) et
 al. on history dependencies with the driven-vortex-solid state of
 YBa2Cu3O7-d single crystals. The authors demonstrate that much of the
 dynamic behavior of the vortex system can be understood in terms of two
 dynamic states, one relatively ordered and the other more disordered.
 Irrespective of prior structural changes, the driven dynamic system has
 a tendency to stabilize on two specific voltage levels: a relatively
 high level, indicative of the ordered dynamic state, and a much lower
 level, indicative of a disordered state. Oscillations of the voltage
 amplitude, observed on applying an asymmetric drive, can be understood
 in terms of periodic changes over time in the proportions of two
 distinct domains, one in the ordered phase, the other disordered. The
 authors found support for this interpretation from the behavior of
 transient responses upon switching between asymmetric and unidirectional
 drives. From an analysis of such transient responses, the authors were
 able to demonstrate the stability of the ordered dynamic phase.
<p>
 A detailed investigation of history effects in the magnetic hysteresis
 of pure YBa2Cu3O7-d single crystals with various types and densities of
 pinning sites has been carried out by S. Kokkaliaris (Southampton) et
 al. The authors used a partial-magnetization-loop technique that
 enabled the authors to detect the point where topological disorder first
 invades the vortex system. Studies of detwinned single crystals with
 very low densities of point defects revealed a transition in the mixed
 state of the superconductor separating a dislocation-free Bragg glass
 from a highly disordered vortex phase. The transition line was
 identified in the field-temperature phase diagram and found to lie near
 the onset of the second magnetization peak. Above the transition,
 metastable topological defects proliferate in the vortex lattice,
 resulting in prominent history effects in the critical current. A high
 concentration of twins as well as low densities of columnar defects
 suppress the transition and eliminate the memory effects.
<p>
 A phenomenological model to describe history effects and metastability
 in the magnetization of weakly pinned superconductors is proposed in a
 preprint by G. Ravikumar (BARC) et al. The authors note that it
 accounts for the experimentally observed history-dependent behavior of
 the critical current density and metastability of the vortex state prior
 to and across the peak-effect region of superconducting systems such as
 NbSe2, CeRu2, and YBa2Cu3O7-d. The model reduces to the Bean critical-
 state model as a limiting case.
<p>
 Local magnetic measurements in a fixed field as a function of
 temperature [m_H(T)] in Nd1.85Ce0.15CuO4-d (NCCO) and untwinned
 YBa2Cu3O7-d (YBCO) crystals have been carried out by D. Giller et al.
 (Bar-Ilan). Both crystals show an abrupt increase in m_H(T) at a field-
 dependent temperature. Moreover, both crystals exhibit a pronounced
 kink in the local magnetization vs field [m_T(H)] curve at a fixed
 temperature T. While in YBCO these anomalies occur along the same line
 in the field-temperature plane, in NCCO the (B,T) locations of the
 anomalies do not coincide. In both crystals the anomalies in m_T(H) are
 identified as signifying a vortex solid-solid disorder-induced
 transition. However, the authors show that the anomalies in m_H(T),
 though associated with the vortex solid-solid transition, do not
 necessarily indicate the location of the transition.
<p>
 Supercooling across a first-order transition in vortex matter has been
 considered theoretically by P. Chaddah and S. B. Roy (Indore). The
 authors find that the observable region of metastability of the
 supercooled phase should depend upon the path followed in H-T space;
 they predict that this region is larger when T is lowered at constant H
 than when H is lowered at constant T.
<p>
 Using large-scale molecular dynamics simulations on samples with nearly
 one million pinning sites, C. Reichhardt (Michigan and UC-Davis) et al.
 have investigated the pinning and driven dynamics of vortices
 interacting with twin boundaries. For low applied driving forces, the
 vortex lattice orients itself parallel to the twin boundary, and the
 authors observe the creation of a flux gradient and vortex-free region
 near the edges of the twin boundary. For increasing drive, the authors
 found evidence for several distinct dynamical flow phases characterized
 by the density of defects in the vortex lattice, the microscopic vortex-
 flow patterns, and the orientation of the vortex lattice. The different
 dynamical phases can be directly related to microscopically measurable
 voltage-current (V-I) curves and voltage noise.
<p>
 A related paper by F. Nori (Michigan) and C. Reichhardt (UC-Davis)
 reports a numerical investigation of the depinning and dynamics of
 vortex lattices in superconductors with square arrays of pinning sites.
 The authors considered vortex motion for varying angles of the driving
 force relative to the pinning lattice in incommensurate magnetic fields
 above the first matching field, such that interstitial vortices are
 present. The authors found that maximum pinning occurs for drives at an
 angle of 45 degrees with respect to the pinning lattice.
<p>
 The stochastic transport of vortices in superconductors by ac current
 rectification has been studied by J. F. Wambaugh (Michigan) et al. using
 numerical simulations. The simulated system acts as a vortex pump,
 lens, or rectifier because the applied electrical ac is transformed into
 a net dc motion of vortices. Thermal fluctuations and the asymmetry of
 the ratchet channel walls induce this diode effect.
<p>
<p>
 More Vortices
<p>
 The effects of weak point disorder on the vortex-matter phase diagram
 have been studied by T. Nishizaki (Tohoku) et al. The authors studied
 the effects of irradiation by 2.5 MeV electrons upon the magnetization
 curves of untwinned YBa2Cu3O7-d single crystals. The authors found that
 point disorder lowers the critical point H_[cp]of the first-order
 vortex-lattice melting line H_m(T) and has an opposite effect on the
 vortex-glass phase boundary above and below H_[cp]. Below H_[cp], the
 field-driven disordering transition line H*(T) between the Bragg glass
 and the vortex-glass phases shifts to lower fields, and the vortex-glass
 phase is expanded after irradiation.
<p>
 The Bose-glass transition in the fully isotropic (K,Ba)BiO3
 superconductor with columnar defects produced by irradiation with 7.2
 GeV Ta ions has been studied by T. Klein (Grenoble) et al. using
 transport and nonlinear susceptibility measurements. For fields below
 the dose-equivalent field B_[phi], the Bose-glass transition line
 H_[BG](T) was found to shift progressively upwards with increasing dose:
 dH_[BG]/dT proportional to 1 + alpha[B]_[phi]^[1/2]. The authors also
 deduced critical exponents from the scaling properties of the transport
 measurements: z = 5.3+-0.3 and nu = 1.1+-0.2. For tilted magnetic
 fields, the transition temperature was found to behave as T_[BG](0) -
 T_[BG](theta) proportional |sin-theta|^[1/nu], as recently suggested by
 Lidmar and Wallin.
<p>
 The supercurrent along the weakly conducting c-axis direction in layered
 superconductors has been studied by R. Hlubina et al. (Comenius). The
 authors considered the case of vortices pinned by screw dislocations
 with Burgers vectors parallel to the c axis, and they found that the
 critical current of small samples is enhanced with respect to the
 perfect crystal, since each dislocation is able to carry a supercurrent
 I_0.
<p>
 Two preprints by M. R. Koblischka (SRL-ISTEC) et al. report observations
 of instabilities (macroturbulence) in the critical state of NdBa2Cu3O7-d
 single crystals. Signatures of such instabilities were found in both
 magneto-optical observations and SQUID magnetometry.
<p>
 A numerical method for calculating zero-temperature equilibrium vortex-
 line configurations in bulk anisotropic type-II superconductors has been
 developed by W.A.M. Morgado and G. Carneiro (Rio de Janeiro). The
 method, which assumes that the vortex lines are straight and arranged in
 a periodic lattice, is designed to search for the minimum of the Gibbs
 free energy in the London approximation. The authors apply the method
 to two physical problems: (a) the magnetic induction vs applied field
 for an isotropic superconductor and (b) the zero-temperature phase
 diagram for a superconductor containing a square lattice of columnar
 defects.
<p>
 General expressions are given in a paper by G. Carneiro (Rio de Janeiro)
 and E. H. Brandt (MPI-Stuttgart) for the magnetic field and energy of
 arbitrary arrangements of straight and curved vortices in an anisotropic
 superconducting film of finite thickness within anisotropic London
 theory. As examples, the authors consider the magnetic field and
 interaction of straight perpendicular vortex lines in films of finite
 thickness.
<p>
<p>
 YBa2Cu3O7-d
<p>
 The effects of annealing treatments on Tc of Ni-substituted YBa2Cu3O7-d
 have been studied by S. Adachi et al. (SRL-ISTEC). Ceramic samples of
 YBa2Cu3-xNixO7-d (x = 0.00, 0.02, 0.05, and 0.10) prepared in 1 atm
 oxygen atmosphere were annealed at 800-1000oC in various atmospheres
 with different oxygen partial pressures and were subsequently oxygenated
 below 550oC. The lower the oxygen partial pressure, the lower the Tc.
 For the samples with fixed x but different Tcs, no appreciable
 difference in lattice parameter and oxygen content was observed. The
 results indicate that the Tc of Ni-substituted YBa2Cu3O7-d can be
 controlled by changing the oxygen partial pressure during annealing, and
 that the distribution of Ni atoms between the chain and plane sites is
 probably altered by the annealing treatment.
<p>
 Systematic measurements of the in-plane fluctuation magnetoconductivity
 in a YBa2Cu3O7-d single crystal have been made by R. M. Costa (Porto
 Alegre) et al. Fields up to 500 mT were applied parallel or
 perpendicular to the CuO2 planes. Far from the transition, the data
 reveal a Gaussian-fluctuation regime, but closer to Tc, the results show
 a critical regime, where the exponent is consistent with predictions for
 the 3D XY universality class with model-E dynamics. Still closer to Tc,
 the authors find evidence for a fluctuation regime beyond 3D XY. The
 authors interpret this behavior as revealing the first-order character
 of the in-field superconducting transition in YBa2Cu3O7-d.
<p>
 Measurements of the first and third harmonics of the complex
 susceptibility (chi_i' + jchi_i"; i = 1 and 3) in YBCO single crystals
 with different oxygen content (6.5 <= x <= 7) are reported by A. J.
 Moreno and V. Bekeris (Buenos Aires). The amplitude of the ac field was
 varied in the presence of an external dc field, both fields being
 parallel to the c axis. The authors found evidence that deoxygenation
 leads to a reduction of bulk pinning strength and consequently to a
 stronger contribution of geometrical barriers. These results support
 recently reported investigations showing that deoxygenation makes the
 YBCO crystals more anisotropic, thus reducing the effective pinning
 barriers for quasi-two-dimensional vortices.
<p>
<p>
 Bi Cuprates
<p>
 Extensive first-principles angle-resolved photointensity (ARPES)
 simulations for Bi2Sr2CaCu2O8+d (Bi-2212) have been carried out by A.
 Bansil (Northeastern) and M. Lindroos (Tampere), who modeled the
 photoemission process realistically by taking into account the full
 crystal wave functions of the initial and final states in the presence
 of the surface. The authors found that the spectral weight of the ARPES
 features associated with the CuO2-plane bands undergoes large and
 systematic variations with k_[parallel] as well as with the energy and
 polarization of the incident photons. The theoretical results are in
 good accord with the corresponding measurements, indicating that the
 remarkable observed changes in the spectral weights in Bi-2212 are
 essentially a matrix-element effect and that the importance of matrix
 elements should be kept in mind when analyzing ARPES spectra in the
 high-Tc superconductors.
<p>
 Measurements of the thermal conductivity of optimally doped Bi-2212 at
 very low temperatures are reported by M. Chiao (McGill) et al. The
 authors observed a residual linear term and used it to extract the ratio
 of quasiparticle velocities v_F/v_2, a parameter in the low-energy d-
 wave spectrum that also governs the linear drop in superfluid density
 with temperature. A comparison with penetration-depth data reveals a
 sizable renormalization, due to quasiparticle interactions, which is of
 comparable magnitude in Bi2Sr2CaCu2O8+d and YBa2Cu3O7-d. The authors
 discuss their findings in the context of photoemission and specific-heat
 studies.
<p>
 The resistivity and thermopower for a set of single crystals of
 Bi2Sr2Ca1-xRxCu2O8+d (R = Er and Pr) have been measured by I. Terasaki
 et al. (Waseda). The authors found that (a) the resistivities of the
 parent insulators exhibit a confinement behavior above T_[max], which is
 near the Neel temperature, and (b) the thermopower shows good scaling
 behavior with a scaling temperature T_[scale], which is near the
 pseudogap temperature. The results show that there are strong
 similarities in the behavior of the antiferromagnetic insulators and the
 high-temperature superconductors.
<p>
<p>
 Other Cuprates
<p>
 Using Cu NQR in Eu-doped La2-xSrxCuO4, G. B. Teitel'baum (Kazan) et al.
 have found evidence for the pinned stripe phase at 1.3 K for 0.08 <= x
 <= 0.18. The pinned fraction increases by one order of magnitude near
 hole doping x = 1/8. The NQR lineshape reveals three inequivalent Cu
 positions: (a) sites in the charge stripes, (b) nonmagnetic sites
 outside the stripes, and (c) sites with a magnetic moment of 0.29 mu_B
 in the antiferromagnetically correlated regions. A dramatic change of
 the NQR signal for x > 0.18, correlating with the onset of bulk
 superconductivity, corresponds to the depinning of the stripe phase.
<p>
 Measurements of the resistivity, magnetoresistance, and penetration
 depth have been made by K. Karpinska (Warsaw) et al. on films of
 La1.85Sr0.15CuO4 with up to 12 at% of Zn substituted for Cu. The
 results show that the quadratic temperature dependence of the inverse
 square of the penetration depth, indicative of d-wave superconductivity,
 is not affected by doping. The suppression of superconductivity leads
 to a metallic nonsuperconducting phase, as expected for a pairing
 mechanism related to spin fluctuations. The metal-insulator transition
 occurs in the vicinity of k_Fl ~~ 1 and appears to be disorder-driven,
 with the carrier concentration unaffected by doping.
<p>
 A preprint by C. Panagopoulos (IRC-Cambridge) et al. reports
 measurements of the absolute values and temperature dependence of the c-
 axis penetration depth lambda_c(T) for two typical single-layer high-Tc
 cuprates, La2-xSrxCuO4 and HgBa2CuO4+d (Hg-1201), as a function of
 doping. The authors observed a distinct change in the behavior of
 lambda_c near 0.20 holes/Cu, which is related to the opening of the
 normal-state pseudogap. The variation of lambda_c with doping is
 qualitatively similar to that of the in-plane component lambda_[ab],
 suggesting that both quantities are strongly affected by the presence of
 the normal-state pseudogap, as is the superconducting condensation
 energy. The strong doping dependence of lambda_c(0) for p < 0.20
 provides an explanation for the discrepancies in the literature.
<p>
 By analysis of the Raman spectra of superconducting YBa2Cu4O8 (Y-124),
 J. Baeckstroem (Chalmers) et al. have observed a suppression of the low-
 energy density of states, which the authors link to changes in the
 linewidth of the Ba-phonon mode. These effects occur at a temperature
 below 150 K, where anomalies in the resistivity and other physical
 properties also take place. The authors argue that these changes in the
 Raman spectra of Y-124 are associated with the opening of a pseudogap.
 Analogous anomalies in the resistivity and the Ba-phonon width in the
 nonsuperconducting homologue PrBa2Cu4O8 (Pr-124) below 150 K suggest
 that similar pseudogap effects can occur without a transition to a
 superconducting state following at a lower temperature.
<p>
 Samples of the Hg1-xRexBa2Ca2Cu3O8+d [(Hg,Re)-1223] superconductor with
 low Re content (x = 0.05) have been produced by M.T.D. Orlando (Rio de
 Janeiro and Vitoria) et al. using a novel thermobaric analysis (TBA)
 that can monitor the total pressure inside the quartz tube during high-
 temperature synthesis. The authors found that reducing the oxygen
 content in the precursor (Re0.05Ba2Ca2Cu3O8+d) and increasing the Hg
 partial pressure inside the quartz tube enhanced the yield of
 superconducting phase. Resistance measurements as a function of
 temperature under hydrostatic pressure (0-1.0 GPa) showed an increase in
 the superconducting transition temperature Tc, which can be fitted with
 a parabolic curve. The authors found that the reduction of the lattice
 volume induced by external hydrostatic pressure is similar to the one
 induced by chemical pressure due to Re doping (0.00 < x < 0.10).
 However, Tc was found not to depend on the chemical pressure. The
 authors explain the behavior on the basis of the pressure-induced
 charge-transfer model (PICTM), as modified by C. C. Almasan et al.
 [Phys. Rev. Lett. 69, 680 (1992)].
<p>
 Measurements of the microwave surface impedance Z_s(T) = R_s(T) +
 iX_s(T) and the complex conductivity sigma_s(T) of high-quality high-Tc
 single crystals of YBa2Cu3O7-d (Y-123), Bi2Sr2CaCu2O8+d (Bi-2212),
 Tl2Ba2CaCu2O8+d (Tl-2212), and Tl2Ba2CuO6+d (Tl-2201) have been analyzed
 by M. R. Trunin (Chernogolovka) et al. The authors compare experimental
 data of Z_s(T) and sigma_s(T) with calculations based on a modified two-
 fluid model that includes temperature-dependent quasiparticle scattering
 and a special temperature variation of the density of superconducting
 carriers. The authors compare the experimental data with their
 calculations and obtain generally good agreement, though some
 disagreements remain.
<p>
<p>
 Films
<p>
 Smooth and flat epitaxial (Hg,Re)Ba2CaCu2O6+d [(Hg,Re)-1212] thin films
 containing no appreciable pinholes or outgrowths have been fabricated by
 N. Inoue (SRL-ISTEC) et al. Films of thickness about 75 nm were
 prepared on (100) SrTiO3 substrates using a two-step process: (a)
 preparation of thin (approximately 100 nm) Re0.1Ba2CaCu2Oz precursor
 films using a pulsed-laser-deposition (PLD) technique and (b) heat
 treatments in a Hg-vapor atmosphere. Homogeneous films with smooth
 surfaces were obtained by simply using precursor films thinner than
 those previously employed, which were thicker than 200 nm. The average
 roughness of the thin (Hg,Re)-1212 films was about 3-4 nm and the
 maximum peak-to-bottom surface roughness was about 10 nm. The as-
 fabricated films exhibited Tcs typically in the range 109-117 K,
 substantially lower than that of the optimally doped bulk (127 K) and
 approximately 5 K lower than the values previous reported for thicker
 films. However, the self-field Jc values measured using bridges
 patterned in the film were reproducibly (3-10) x 10^6 A/cm^2 at 77 K and
 as high as (2-3) x 10^6 A/cm^2 at 100 K.
<p>
 A preprint by Y.-Y. Xie (Kansas) et al. reports that the fabrication
 process for HgBa2CaCu2O6+d (Hg-1212) superconducting thin films can be
 greatly simplified when air-insensitive precursor films (TlyBa2CaCu2Ox)
 are employed. Using such precursors, the authors were able to
 reproducibly fabricate high-quality Hg-1212 films in air. Zero-
 resistance transition temperatures were typically 122-124 K. The self-
 field critical current densities Jc were up to 2.0 x 10^7 A/cm^2 at 5 K,
 remaining above 10^6 A/cm^2 at 100 K.
<p>
 The synthesis by molecular beam epitaxy (MBE) and the structural
 characterization of a new superconducting barium cuprate Ba2CuO4-d (Tc
 <= 90 K) are described in a paper by H. Yamamoto et al. (NTT).
 Important factors are (a) the preparation of Ba2CuO3 in a CO2/H2O-free
 environment and (b) the structural transformation from insulating
 Ba2CuO3 with 1D CuO chains to superconducting Ba2CuO4-d with 2D CuO2
 planes by strong ozone oxidation after growth.
<p>
 Preprints by M. Naito and S. Karimoto (NTT) and by S. Karimoto and M.
 Naito (NTT) report the synthesis by MBE of a new superconducting lead
 cuprate PbSr2CuO5+d (Pb-1201), which has Tc ~ 40 K and a pure PbO
 charge-reservoir block. The authors note that the keys to successful
 synthesis of Pb-1201 are low-temperature growth and an appropriate
 choice of substrate materials. Synthesis of higher members in the Pb-
 12(n-1)n homologous series has not been straightforward because the
 growth temperature is limited by the volatility of Pb and PbOx.
<p>
 A preprint by OE. Festin (Uppsala) et al. reports that the flux-noise
 spectrum and complex impedance for a 500 Angstroms thick YBCO film have
 been measured and compared with predictions for two-dimensional vortex
 fluctuations. The authors verified that the complex impedance and the
 flux-noise spectra are proportional to each other, that the logarithm of
 the flux-noise spectra vs the logarithm of the frequency for different
 temperatures has a common tangent with slope ~~ -1, and that the
 amplitude of the noise decreases as d^[-3], where d is the height above
 the film at which the magnetic flux is measured. The authors found what
 appears to be a crossover from normal to anomalous vortex diffusion,
 which they discuss in terms of a two-dimensional decoupling.
<p>
 An array of miniature Hall sensors has been used by E. Sheriff et al.
 (Bar-Ilan) to measure the spatial distribution and time evolution of the
 local induction in a thin YBa2Cu3O7-d film in the remanent state before
 and after the application of a dc transport current. After the
 transport current is applied, the induction peak is shifted from the
 center of the sample, indicating an inhomogeneous current distribution.
 Transport current markedly changes the spatial distribution of the
 electric field and the relaxation rate, creating a dynamic neutral line
 where the electric field is maximum and the relaxation rate is zero.
<p>
 A preprint by M. Naito et al. (NTT) stresses that the reason good tunnel
 junctions in high-Tc superconductors are so difficult to fabricate is
 that significant oxygen deficiencies readily occur near the interface
 with overlayers.
<p>
<p>
 Applications
<p>
 A spectrometer incorporating a high-Tc superconducting quantum
 interference device (SQUID) has been used by K. Schlenga et al. (UC-
 Berkeley and LBNL) to obtain nuclear magnetic resonance signals from
 protons in mineral oil at room temperature in fields up to 3 mT. The
 spatial separation between the SQUID magnetometer at 77 K and the sample
 at room temperature is less than 1 mm. At 2 mT, the signal is easily
 resolved in a single scan. The authors obtained two-dimensional images
 of samples consisting of pieces of lucite or glass immersed in mineral
 oil at 2 mT.
<p>
 A preprint by E. J. Romans et al. (Strathclyde) reports theoretical and
 experimental studies of the low-frequency behavior of discrete HTS
 Josephson vortex-flow transistors. The devices were fabricated from
 YBa2Cu3O7-d thin films grown on 24 degrees SrTiO3 bicrystal substrates.
 They consist of an asymmetric array of 10 or 20 Josephson junctions,
 with a control current fed through an independent line that is
 inductively coupled to the array. The authors have measured current
 gains up to 40 at 77 K and substantially higher at lower temperatures.
 The authors discuss the results of simulations of the device behavior
 and consider the effects of junction critical current, number of
 junctions, and array loop inductance. The authors compare the measured
 device behavior at 77 K with simulations that include the effects of
 thermal noise.
<p>
 The levitation force between Nd-Fe-B permanent magnets and YBCO bulk
 superconductors has been measured by K. Nagashima (SRL-ISTEC and Railway
 Technical Research Institute) et al. under varying magnet
 configurations. The authors varied the number of poles, the thickness
 of the magnets, and the shape of the bulk superconductors, and they
 added back iron yokes. The authors found the levitation force to be
 strongly dependent on the magnet configuration, and thus they concluded
 that for maximizing the levitation force of magnetic bearings in a
 superconducting flywheel system, it is important to optimize the
 arrangement of permanent magnets.
<p>
 An analysis of the ac losses in a silver-sheathed Bi-2223
 multifilamentary tape has been carried out by M. Sugimoto (Furukawa
 Electric) et al. to show that twisting the filaments can reduce the
 losses. The authors find that the ac losses in external ac magnetic
 fields parallel to the tape surface consist mainly of the ac losses due
 to (a) macroscopic screening currents among the multiple filaments and
 (b) microscopic screening currents in the grains. The authors find that
 the former loss depends strongly on the filament pitch, while the latter
 does not. The authors' analytical model should be useful for optimizing
 the performance of Bi-2223 tapes with respect to the cross-sectional
 dimensions, number of filaments, matrix resistivity, filament twist
 pitch, and critical current.
<p>
<p>
 Theory
<p>
 The effects of dilute nonmagnetic impurities on the frequency dependence
 of Im[chi](Q,omega) have been studied by N. Bulut (Koc) within the
 framework of the 2D Hubbard model using the random-phase approximation.
 The calculations were motivated by neutron-scattering data on Zn-
 substituted YBa2Cu3O7-d. The author discusses the origin of the peak
 and of the low-frequency spectral weight induced by the impurities.
<p>
 A preprint by T. K. Ng (HKUST) proposes a duality relation between
 antiferromagnetism and d-wave superconductivity in the t-J model. The
 topological spin and charge excitations in one phase have the same
 dynamics as elementary excitations in the other phase, except for energy
 gaps. The author constructs a plausible phase diagram of the t-J model.
<p>
 Zeeman and orbital effects of an in-plane magnetic field on high-Tc
 cuprate superconductors have been studied by K. Yang (NHMFL and Florida
 State) and S. L. Sondhi (Princeton). The authors find that the orbital
 effect is qualitatively different for in-plane and interlayer mechanisms
 of superconductivity. For in-plane mechanisms, interlayer couplings may
 be modeled via weak interlayer Josephson coupling, whose effects
 disappear as H -->infinity, in which case the Zeeman effect dominates.
 For the interlayer mechanism, in which the Josephson coupling is the
 driving force for superconductivity, the in-plane field suppresses
 superconductivity, yielding an upper bound for H_[c2], which the authors
 estimate.
<p>
 Using the linearized Eilenberger equations, W. Kim (TCSUH and Hsinchu)
 et al. have studied the upper critical field H_[c2] of mixed d- and s-
 wave superconductors, accounting for the competing effects of mass
 anisotropy and spin Zeeman coupling. The authors find that mass
 anisotropy always enhances H_[c2], while the Zeeman interaction
 suppresses H_[c2]. As required by thermodynamics, H_[c2] saturates at
 zero temperature. The authors compare their theoretical calculations
 with recent experimental data on YBa2Cu3O7-d.
<p>
 A new method permitting the study of multiple coherent reflections or
 transmissions by partially transparent interfaces (e.g., in multilayer
 mesoscopic structures or grain boundaries in high-Tc superconductors) is
 proposed in a preprint by A. Shelankov and M. Ozana (Umea), who use the
 framework of the quasiclassical theory of superconductivity. The
 authors apply their method to study the behavior of (a) a film separated
 from a bulk superconductor by a partially transparent interface and (b)
 a two-layer system with an arbitrary transparent interface.
<p>
 A preprint by T. Dahm (MPI-Dresden and Tuebingen) investigates the
 influence of a pseudogap upon the isotope-effect exponent. Within
 different approximations, the author finds that the pseudogap strongly
 increases the isotope exponent, in qualitative agreement with
 experiments on underdoped high-Tc superconductors. The author's result
 is stable against strong-coupling self-energy corrections and also holds
 for recently proposed spin-fluctuation-exchange models if a weak
 additional electron-phonon coupling is considered.
<p>
 A unifying scenario for the critical behavior of YBa2Cu3O7-d (Y-123) and
 Bi2Sr2CaCu2O8+d (Bi-2212) has been proposed by C. de Calan and F. S.
 Nogueira (Ecole Polytechnique). The authors find that both critical
 crossovers observed in these materials follow by considering two
 different scalings in the dual Ginzburg-Landau model. The first scaling
 leads to the critical exponents nu ~~ 2/3 for the correlation length,
 nu' ~~ 1/3 for the magnetic field penetration depth, and alpha ~~ 0 for
 the specific heat, in agreement with exponents obtained for Y-123 single
 crystals. For the second scaling, the authors obtain nu = 1 and alpha =
 -1, which should be compared with the measured values nu ~~ 1 and
 alpha~~ -0.7 for Bi-2212. The authors predict the value nu' = 1 for the
 penetration-depth exponent in Bi-2212.
<p>
<p>
 Other Activities
<p>
 Puzzling results recently were published by V. I. Tsebro et al. in JETP
 Lett. 70, 462 (1999). The authors found that the magnetization curves
 of samples of fragments of cathode carbon deposits with a high content
 of multiwalled nanotubes exhibited hysteretic magnetization, suggesting
 the induction of persistent currents in the samples and magnetic flux
 trapping, as in multiply connected superconducting structures. No
 decrease of the trapped flux with time was observed at helium
 temperatures over a measurement time of about 20 h. For intermediate
 (~30 K) and room temperatures, the trapped magnetic flux decayed slowly
 with characteristic relaxation times of the order of 150 h and 15 h,
 respectively.
<p>
 The intergranular transport properties of polycrystalline samples of
 Sm1.82Ce0.18CuO4-y (SCCO) exhibiting a double resistive superconducting
 transition have been studied by M.J.R. Sandim (Lorena) and R. F. Jardim
 (Sao Paulo). The samples consisted of small islands that undergo a
 superconducting transition at T_[ci] ~ 21 K but for which long-range
 phase coherence is achieved through Josephson coupling only at a lower
 temperature T_[cJ] ~ 10 K. The authors concluded that magnetoresistance
 is associated with dissipation due to Josephson vortex motion (flux
 flow), and they obtained the field and temperature dependence of the
 corresponding intergranular activation energy.
<p>
<p>
 Overview
<p>
 A preprint by F. Sandiumenge (Barcelona) et al. summarizes the major
 factors constraining the development of microstructures during melt
 processing in Y-123 materials. The authors then discuss recent results
 on alternative processing routes that allow a selective modification of
 the dislocation substructure in melt-processed materials. Substantial
 increases of up to 180% in the critical current density Jc have been
 achieved. The authors also discuss the effect of rare-earth
 substitutions on the dimensionality of the dislocation substructure (34
 refs.).
<p>
<p>
 Ph.D. Thesis
<p>
 Since their discovery in 1994, the quaternary borocarbides RN2B2C have
 generated intensive research activity because they are ideal systems for
 studying the interplay of magnetism and superconductivity, and they
 exhibit an interesting variety of commensurate and incommensurate
 magnetic structures. The ETH Zurich Ph.D. thesis of U. Gasser presents
 a study of the magnetic properties of the borocarbides containing heavy
 rare earths, with special emphasis on the compounds that display
 coexistence of antiferromagnetism and superconductivity (R = Dy, Ho, Er,
 and Tm). The author performed both elastic and inelastic neutron
 scattering experiments to investigate both structure and excitations.
 In addition, the author combined the neutron-scattering results with
 information from specific-heat, susceptibility, Mossbauer, and mu+SR
 experiments (126 refs.).
<p>
<p>
 Contributed by John R. Clem
 <hr>
<p>
 Contents: Preprints begin on page 7; Coming Events begin on page 14;
 and Resources are on page 15.
<p>
<p>
 High-Tc Update is available without charge to interested persons.
 Recipients are expected to participate in this information exchange by
 sending us preprints, reprints, meeting news, research news, etc.
 Contributions to defray the cost of newsletter printing and mailing are
 welcome.
 <hr>
<p>
 PREPRINTS
 To obtain a particular preprint, contact the first author at the address
 given at the end of the citation. Help us expand this list by sending
 us your complete preprint. Please specify where and when your paper was
 submitted. An * next to an entry indicates it is a correction or
 revision of a previous entry. PACS codes and/or key words are given at
 the end of the citation.
<p>
 S. Adachi, Y. Itoh, T. Machi, E. Kandyel, S. Tajima, and N. Koshizuka,
 "Control of Tc for Ni-Substituted YBa2Cu3O7-d by Annealing Treatments."
 To be published in Phys. Rev. B. Superconductivity Research Laboratory,
 International Superconductivity Technology Center (ISTEC), 10-13
 Shinonome 1-chome, Koto-ku, Tokyo 135, JAPAN. 74.72.Bk; 74.62.Bf;
 74.62.Dh.
<p>
 R. P. Aloysius, A. Sobha, P. Guruswamy, K.G.K. Warrier, and U.
 Syamaprasad, "Fabrication of (Bi,Pb)-2223/Ag-Cu Alloy Sheathed Tapes:
 Optimization of Cu Composition in the Sheath with Respect to the Cu
 Stoichiometry in the System." To be published in Physica C (in press).
 Contact U. Syamaprasad, Regional Research Laboratory (CSIR), Council of
 Scientific and Industrial Research, Trivandrum 695 019, INDIA; telephone
 +91 471 491712; telefax +91 471 490186; e-mail
 <a href="mailto:smail@csrrltrd.ren.nic.in">smail@csrrltrd.ren.nic.in.</a> Key words: (Bi,Pb)-2223/Ag-Cu tapes, Cu
 composition, phase evolution, critical current density (Jc).
<p>
 J. Baeckstroem, M. Ruebhausen, M. Kaell, L. Boerjesson, A. P.
 Litvinchuk, M. Kakihana, M. Osada, and B. Dabrowski, "Raman Scattering
 in YBa2Cu4O8 and PrBa2Cu4O8: Indications of Pseudogap Effects in Non-
 Superconducting PrBa2Cu4O8." Submitted to Phys. Rev. B. Department of
 Applied Physics, Chalmers University of Technology, S-41296 Goeteborg,
 SWEDEN; telephone +46 31 772 1000; telefax +46 31 772 2090; e-mail
 <a href="mailto:backstr@fy.chalmers.se">backstr@fy.chalmers.se.</a> 74.72.Bk; 74.72.Jt; 74.25.Kc; 78.30.-j.
<p>
 A. Bansil and M. Lindroos, "Importance of Matrix Elements in the ARPES
 Spectra of BISCO." To be published in Phys. Rev. Lett. Department of
 Physics, Northeastern University, Boston, MA 02115; preprint also
 available at <a href="http://xxx.lanl.gov/abs/cond-mat/9910496">http://xxx.lanl.gov/abs/cond-mat/9910496.</a> 79.60.Bm;
 71.18.+y; 74.72.Hs.
<p>
 H. Boyaci, Z. Gedik, and I. O. Kulik, "Superconductivity in Mesoscopic
 Metal Particles: The Role of Degeneracy." Department of Physics,
 Bilkent University, Ankara 06533, TURKEY; e-mail
 <a href="mailto:boyaci@fen.bilkent.edu.tr">boyaci@fen.bilkent.edu.tr;</a> preprint also available at
 <a href="http://xxx.lanl.gov/abs/cond-mat/9909386">http://xxx.lanl.gov/abs/cond-mat/9909386.</a>
<p>
 N. Bulut, "Effects of Dilute Nonmagnetic Impurities on the Q = (pi, pi)
 Spin-Fluctuation Spectrum in YBa2Cu3O7." Department of Mathematics, Koc
 University, Istinye 80860 Istanbul, TURKEY; e-mail <a href="mailto:nbulut@ku.edu.tr">nbulut@ku.edu.tr;</a>
 preprint also available at <a href="http://xxx.lanl.gov/abs/cond-mat/9909437">http://xxx.lanl.gov/abs/cond-mat/9909437.</a>
 74.62.Dh; 74.72.Bk; 75.10.Lp; 74.25.-q.
<p>
 Gilson Carneiro and Ernst Helmut Brandt, "Vortex Lines in Films: Fields
 and Interactions." To be published in Physica C. Instituto de Fisica,
 Universidade Federal do Rio de Janeiro, C.P. 68528, 21945-970 Rio de
 Janeiro, BRAZIL. 74.60.Ec.
<p>
 P. Carretta, A. Lascialfari, A. Rigamonti, A. Rosso, and A. Varlamov,
 "Superconducting Fluctuations and Anomalous Diamagnetism in Underdoped
 YBa2Cu3O6+x from Magnetization and [63]^Cu NMR-NQR Relaxation
 Measurements." E-mail <a href="mailto:pietro.carretta@pv.infn.it">pietro.carretta@pv.infn.it,</a> preprint available at
 <a href="http://xxx.lanl.gov/abs/cond-mat/9911182">http://xxx.lanl.gov/abs/cond-mat/9911182.</a>
<p>
 P. Chaddah and S. B. Roy, "Supercooling Across First-Order Phase
 Transitions in Vortex Matter." Submitted to Pramana - J. Phys. Low
 Temperature Physics Laboratory, Centre for Advanced Technology, Indore
 452 013, INDIA; e-mail <a href="mailto:sbroy@cat.ernet.in">sbroy@cat.ernet.in;</a> preprint also available at
 <a href="http://xxx.lanl.gov/abs/cond-mat/9910437">http://xxx.lanl.gov/abs/cond-mat/9910437.</a> Key words: supercooling,
 metastability, magnetic-field variation, first-order transition.
 64.60.My; 64.70.Dv; 74.60.-w.
<p>
 K. Chen, L. Chen, T. Yang, J. P. Wang, P. J. Wu, D. N. Zheng, and Z. X.
 Zhao, "High-Tc SQUID Magnetometer with Grain Boundary Junctions and Its
 Application in Non-Destructive Evaluation." To be published in Physica
 C (in press). Contact D. N. Zheng, National Laboratory for
 Superconductivity, Institute of Physics, Chinese Academy of Sciences,
 P.O. Box 603-38, Beijing 100080, PEOPLE'S REPUBLIC OF CHINA; e-mail
 <a href="mailto:dzheng@ssc.iphy.ac.cn">dzheng@ssc.iphy.ac.cn.</a> Key words: SQUID, NDE, magnetometer, high Tc.
 85.25.Dq.
<p>
 May Chiao, P. Lambert, R. W. Hill, Christian Lupien, R. Gagnon, Louis
 Taillefer, and P. Fournier, "Low-Energy Quasiparticles in Cuprate
 Superconductors: A Quantitative Analysis." Cavendish Laboratory,
 University of Cambridge, Madingley Road, Cambridge CB3 0HE, UNITED
 KINGDOM; Louis Taillefer's e-mail at University of Toronto
 <a href="mailto:louis@physics.utoronto.ca">louis@physics.utoronto.ca;</a> preprint also available at
 <a href="http://xxx.lanl.gov/abs/cond-mat/9910367">http://xxx.lanl.gov/abs/cond-mat/9910367.</a> 74.70.Tx; 74.25.Fy.
<p>
 Rosangela Menegotto Costa, Paulo Pureur, Miguel Gusmao, Sadok Senoussi,
 and K. Behnia, "Scaling Beyond 3D XY in the Fluctuation Conductivity of
 YBa2Cu3O7-d." To be published in Solid State Commun. Contact Paulo
 Pureur, Instituto de Fisica, Universidade Federal do Rio Grande do Sul,
 Caixa Postal 15051, 91501-970 Porto Alegre, RS, BRAZIL; e-mail
 <a href="mailto:ppureur@if.ufrgs.br">ppureur@if.ufrgs.br.</a> Key words: high-Tc superconductors, electronic
 transport, phase transitions.
<p>
 T. Dahm, "Isotope Effect in the Presence of a Pseudogap." Submitted to
 Phys. Rev. B. Institut fuer Theoretische Physik, Universitaet
 Tuebingen, Auf der Morgenstelle 14, D-72076 Tuebingen, GERMANY;
 telephone +49 7071 29 73434; telefax +49 7071 29 5604; e-mail
 <a href="mailto:thomas.dahm@uni-tuebingen.de">thomas.dahm@uni-tuebingen.de;</a> preprint also available at
 <a href="http://xxx.lanl.gov/abs/cond-mat/9911123">http://xxx.lanl.gov/abs/cond-mat/9911123.</a> 74.72.-h; 74.62.-c; 74.20.-z;
 74.20.Mn.
<p>
 Claude de Calan and Flavio S. Nogueira, "Critical Behavior of YBa2Cu3O7-
 d and Bi2Sr2CaCu2O8+d from the Dual Ginzburg-Landau Model." Centre de
 Physique Theorique, Ecole Polytechnique, F-91128 Palaiseau Cedex,
 FRANCE; Flavio S. Nogueira's e-mail <a href="mailto:nogueira@cpht.polytechnique.fr">nogueira@cpht.polytechnique.fr;</a>
 preprint also available at <a href="http://xxx.lanl.gov/abs/cond-mat/9909356">http://xxx.lanl.gov/abs/cond-mat/9909356.</a>
 74.20.-z; 05.10.Cc; 11.10.-z.
<p>
 D. V. Efremov, M.S. Marenko, M.A. Baranov, and M. Yu. Kagan, "Critical
 Temperature and Phase Diagram for a 2D Superfluid Fermi-Gas with
 Repulsion." To be published in Physica B: Proc. of the 22nd Int. Conf.
 on Low Temp. Phys. (LT22), Helsinki, Finland, Aug. 5-11, 1999. M. S.
 Marenko's e-mail <a href="mailto:maxim@kapitza.ras.ru">maxim@kapitza.ras.ru,</a> preprint available at
 <a href="http://xxx.lanl.gov/abs/cond-mat/9911167">http://xxx.lanl.gov/abs/cond-mat/9911167.</a>
<p>
 Oerjan Festin, Peter Svedlindh, Beom Jun Kim, Petter Minnhagen, Radoslav
 Chakalov, and Zdravko Ivanov, "Vortex Fluctuations in High-Tc Films:
 Flux Noise Spectrum and Complex Impedance." To be published in Phys.
 Rev. Lett. Department of Materials Science, Uppsala University, SE-751
 21 Uppsala, SWEDEN; Beom Jun Kim's e-mail <a href="mailto:kim@tp.umu.se">kim@tp.umu.se;</a> preprint also
 available at <a href="http://xxx.lanl.gov/abs/cond-mat/9910519">http://xxx.lanl.gov/abs/cond-mat/9910519.</a> 74.40.+k;
 74.25.Nf; 74.76.Bz; 74.76.-w.
<p>
 Alexander M. Gabovich and Alexander I. Voitenko, "Non-Stationary
 Josephson Tunneling Involving Superconductors with Spin-Density Waves."
 To be published in Physica C (in press). Department of Crystal Physics,
 Institute of Physics, National Academy of Sciences, Prospekt Nauki 46,
 252650 Kiev-22, UKRAINE; telefax +380 44 265 1589; e-mail
 <a href="mailto:collphen@marion.iop.kiev.ua">collphen@marion.iop.kiev.ua.</a> Key words: tunnel junction, Josephson
 current, quasiparticle current, spin-density waves. 74.50.+r; 74.70.Tx;
 75.30.Fv; 73.40.Gk.
<p>
 Urs Gasser, "Magnetic Properties of the Rare Earth Borocarbides RNi2B2C:
 A Neutron Scattering Study." Submitted as a Ph.D. thesis (Swiss Federal
 Institute of Technology, ETH Zurich). Contact Peter Allenspach,
 Laboratory for Neutron Scattering, ETH Zurich and Paul Scherrer
 Institute, Bldg. WHGA/146, CH-5232 Villigen PSI, SWITZERLAND; telephone
 +41 56 310 2527; telefax +41 56 310 2939; e-mail
 <a href="mailto:peter.allenspach@psi.ch">peter.allenspach@psi.ch.</a>
<p>
 A. Gerashenko, Y. Piskunov, K. Mikhalev, A. Ananyev, K. Okulova, S. V.
 Verkhovskii, A. Yakubovskii, L. D. Shustov, and A. Trokiner, "The
 [63]^Cu and [17]^O NMR Studies of Spin Susceptibility in Differently
 Doped Tl2Ba2CaCu2O8-d Compounds." To be published in Physica C (in
 press). Institute of Metal Physics, Russian Academy of Sciences,
 Kovalevskaya str. 18, Ekaterinburg 620219, RUSSIA; telefax +7 343 274
 5244; e-mail <a href="mailto:gerashenko@ifm.ural.ru">gerashenko@ifm.ural.ru.</a> Key words: [17]^O, [63]^Cu NMR,
 Tl2Ba2CaCu2O8-d, spin fluctuations at CuO2 planes.
<p>
 D. Giller, A. Shaulov, and Y. Yeshurun, "Anomalies in the Temperature
 Dependence of the Local Magnetization in YBa2Cu3O7-d and
 Nd1.85Ce0.15CuO4-d Crystals." To be published in J. Low Temp. Phys.
 Contact Yael Radzyner, Institute of Superconductivity, Department of
 Physics, Bar-Ilan University, Ramat Gan 52900, ISRAEL; e-mail
 <a href="mailto:radzyner@mail.biu.ac.il">radzyner@mail.biu.ac.il.</a> 74.60.Ge; 74.72.-h.
<p>
 Sanjay Gupta, Om. Prakash, B. D. Padalia, I. K. Gopalakrishnan, J. V.
 Yakhmi, and A. K. Patnaik, "The Interrelationship of Cu Effective Charge
 and Superconductivity in the T'-Type Gd1.85-xPrxCe0.15CuOy System." To
 be published in J. Phys.: Condens. Matter. Contact B. D. Padalia,
 Department of Physics, Indian Institute of Technology, Powai, Mumbai 400
 076, INDIA; e-mail <a href="mailto:phbdpia@niharika.phy.iitb.ernet.in">phbdpia@niharika.phy.iitb.ernet.in.</a>
<p>
 R. Hlubina, M. Grajcar, V. Bezak, P. Guba, and K. Karlovsky, "Screw
 Dislocation-Induced Enhancement of the c-Axis Critical Current in
 Anisotropic Superconductors." To be published in Physica C (in press).
 Department of Solid State Physics, Comenius University, Mlynska Dolina
 F2, 842 15 Bratislava, SLOVAKIA; telefax +421 7 654 25 882; e-mail
 <a href="mailto:hlubina@fmph.uniba.sk">hlubina@fmph.uniba.sk.</a> Key words: layered superconductors, critical
 current, dislocations, flux lines. 74.20.De; 74.60.-w; 61.72.Lk.
<p>
 Masatoshi Imada and Masanori Kohno, "Superconductivity from Flat
 Dispersion Designed in Doped Mott Insulators." To be published in Phys.
 Rev. Lett. E-mail <a href="mailto:imada@ginnan.issp.u-tokyo.ac.jp">imada@ginnan.issp.u-tokyo.ac.jp,</a> preprint available
 at <a href="http://xxx.lanl.gov/abs/cond-mat/9911185">http://xxx.lanl.gov/abs/cond-mat/9911185.</a>
<p>
 N. Inoue, T. Sugano, A. Tsukamoto, T. Utagawa, S. Adachi, and K. Tanabe,
 "(Hg,Re)Ba2CaCu2Oy Thin Films with Improved Surface Morphology." To be
 published in Physica C. Superconductivity Research Laboratory,
 International Superconductivity Technology Center (ISTEC), 10-13
 Shinonome 1-chome, Koto-ku, Tokyo 135, JAPAN. Key words: (Hg,Re)-1212
 thin film, surface morphology, defect, Jc. 74.72.Gr; 74.76.Bz; 81.15.-
 z.
<p>
 J. Y. Juang, M. C. Hsieh, C. W. Luo, T. M. Uen, K. H. Wu, and Y. S. Gou,
 "Fluctuation-Enhanced Conductivity in YBa2Cu3Ox (6.5 <= x <= 6.95) and
 Tl2Ba2Ca2Cu3O10+-d Superconducting Thin Films." To be published in
 Physica C (in press). Department of Electrophysics, National Chiao-Tung
 University, 30047 Hsinchu, Taiwan, REPUBLIC OF CHINA; telephone +886 3
 571 2121; telefax +886 3 572 5230; e-mail <a href="mailto:jyjuang@cc.nctu.edu.tw">jyjuang@cc.nctu.edu.tw.</a> Key
 words: fluctuation effects, oxygen stoichiometry, Cu chains, coherence
 length.
<p>
 S. Karimoto and M. Naito, "New Superconducting Lead Cuprates Prepared by
 Molecular Beam Epitaxy." Presented at 5th Int. Workshop on Chemical
 Designing and Processing of High-Tc Supercond. (Chem-HTSC V); to be
 published in Physica C. NTT Basic Research Laboratories, 3-1
 Morinosato-Wakamiya, Atsugi-shi, Kanagawa 243-0198, JAPAN; telefax +81
 462 40 4717; e-mail <a href="mailto:karimoto@with.brl.ntt.co.jp">karimoto@with.brl.ntt.co.jp.</a> Key words:
 PbSr2CuO5+d, Pb-1201, high-Tc superconductor, MBE, homologous series.
<p>
 K. Karpinska, Marta Z. Cieplak, S. Guha, A. Malinowski, T. Skoskiewicz,
 W. Plesiewicz, M. Berkowski, B. Boyce, Thomas R. Lemberger, and P.
 Lindenfeld, "Metallic Nonsuperconducting Phase and d-Wave
 Superconductivity in Zn-Substituted La1.85Sr0.15CuO4." To be published
 in Phys. Rev. Lett. Institute of Physics, Polish Academy of Sciences,
 PL-02668 Warsaw, POLAND; S. Guha's e-mail at Rutgers University
 <a href="mailto:sabya@physics.rutgers.edu">sabya@physics.rutgers.edu;</a> preprint also available at
 <a href="http://xxx.lanl.gov/abs/cond-mat/9911149">http://xxx.lanl.gov/abs/cond-mat/9911149.</a> 74.62.-c; 74.72.Dn; 74.76.Bz;
 74.25.Fy; 74.20.Mn.
<p>
 Hae-Young Kee, Yong Baek Kim, and Kazumi Maki, "Collective Modes and
 Sound Propagation in a p-Wave Superconductor: Sr2RuO4." E-mail
 <a href="mailto:hykee@cooper.physics.ucla.edu">hykee@cooper.physics.ucla.edu,</a> preprint available at
 <a href="http://xxx.lanl.gov/abs/cond-mat/9911131">http://xxx.lanl.gov/abs/cond-mat/9911131.</a>
<p>
 Ali E. Khalil, "Residual Specific Heat and Localized States of Cluster
 Formations in Disordered Superconductivity." To be published in Physica
 C. Department of Physics, Xavier University, 3800 Victory Parkway,
 Cincinnati, OH 45207-4111; telephone (513) 745-3626; telefax (513) 745-
 2070.
<p>
 Wonkee Kim, Jian-Xin Zhu, and C. S. Ting, "Competing Effects of Mass
 Anisotropy and Spin Zeeman Coupling on the Upper Critical Field of a
 Mixed d- and s-Wave Superconductor." To be published in Phys. Rev. B.
 Texas Center for Superconductivity, University of Houston, Houston, TX
 77204-5932; telephone (713) 743-8200; telefax (713) 743-8201; e-mail
 <a href="mailto:preprints@www.tcs.uh.edu">preprints@www.tcs.uh.edu;</a> preprint also available at
 <a href="http://xxx.lanl.gov/abs/cond-mat/9910531">http://xxx.lanl.gov/abs/cond-mat/9910531.</a> 74.20.-z; 74.20.Mn; 74.25.Bt.
<p>
 Y. Kimishima, K. Kamimura, and Y. Ichiyanagi, "ac Magnetic
 Susceptibility by Modified Bean Model with H_[c1]." To be published in
 Physica C (in press). Department of Physics, Faculty of Engineering,
 Yokohama National University, Tokiwadai 79-5, Hodogaya, Yokohama 240-
 8501, JAPAN; telephone +81 45 339 4182; telefax +81 45 339 4182; e-mail
 <a href="mailto:kimi@physics.sci.ynu.ac.jp">kimi@physics.sci.ynu.ac.jp.</a> Key words: mixed state, lower critical
 field, reversible magnetization, penetration field, magnetization, ac
 magnetic susceptibility. 74.20.-z; 74.25.Ha; 74.60.-w; 74.60.Ec;
 74.60.Jg.
<p>
 T. Klein, A. Conde-Gallardo, I. Joumard, J. Marcus, C. J. van der Beek,
 and M. Konczykowski, "Bose Glass Melting in the Cubic (K,Ba)BiO3 High Tc
 Oxide with Columnar Defects." Submitted to Phys. Rev. B. Laboratoire
 d'Etudes des Proprietes Electroniques des Solides, Centre National de la
 Recherche Scientifique, B.P. 166, F-38042 Grenoble Cedex 9, FRANCE;
 telephone +33 4 7688 1008; telefax +33 4 7688 7988; e-mail
 <a href="mailto:klein@lepes.polycnrs-gre.fr">klein@lepes.polycnrs-gre.fr.</a> 74.60.Ge; 74.72.-h.
<p>
 Z. Klencsar, E. Kuzmann, A. Vertes, P.C.M. Gubbens, A. M. van der Kraan,
 M. Bodogh, and I. Kotsis, "Evidence for Pr^[3+] in EuBa1.3Pr0.7Cu3O7-d
 by [141]^Pr Mossbauer Spectroscopy." To be published in Physica C (in
 press). Research Group for Nuclear Methods in Structural Chemistry at
 Eoetvoes University, Hungarian Academy of Sciences, Pazmany Peter Setany
 1/A, H-1117 Budapest, HUNGARY; telephone +36 1 209 0555, ext. 1680;
 telefax +36 1 209 0602; e-mail <a href="mailto:klencsar@para.chem.elte.hu">klencsar@para.chem.elte.hu.</a> Key words:
 Mossbauer, praseodymium, substitution, HTSC. 74.72.-h; 74.72.Bk;
 74.62.Dh.
<p>
 Michael R. Koblischka, Satoru Koishikawa, and Masato Murakami, "Macro-
 Turbulence in the Critical State." To be published in Physica B: Proc.
 of the 22nd Int. Conf. on Low Temp. Phys. (LT22), Helsinki, Finland,
 Aug. 5-11, 1999. Nordic Superconductor Technologies A/S, Priorparken
 685, DK-2605 Brondby, DENMARK; telephone +45 4348-2523 or -2500; telefax
 +45 4348-2501; e-mail <a href="mailto:mk@nst.com">mk@nst.com</a> or <a href="mailto:michael.koblischka@risoe.dk">michael.koblischka@risoe.dk.</a> Key
 words: critical state, instability, flux turbulence.
<p>
 Michael R. Koblischka, Masato Murakami, Satoru Koishikawa, Tom Henning
 Johansen, Michael Baziljevich, Thomas Frello, and Thomas Wolf,
 "Instability of the Critical State in NdBa2Cu3O7-d Single Crystals."
 Presented at the Int. Conf. on Phys. and Chem. of Molecular and Oxide
 Supercond. (MOSą99), Stockholm, Sweden, July 28-Aug. 2, 1999; to be
 published in J. Low Temp. Phys. Nordic Superconductor Technologies A/S,
 Priorparken 685, DK-2605 Brondby, DENMARK; telephone +45 4348-2523 or
 -2500; telefax +45 4348-2501; e-mail <a href="mailto:mk@nst.com">mk@nst.com</a> or
 <a href="mailto:michael.koblischka@risoe.dk">michael.koblischka@risoe.dk.</a>
<p>
 S. Kokkaliaris, A. A. Zhukov, P.A.J. de Groot, R. Gagnon, L. Taillefer,
 and T. Wolf, "Transition from Elastic to Plastic Vortex Phases and Its
 Evolution with Quenched Disorder in YBa2Cu3Oy Single Crystals." To be
 published in Phys. Rev. B. Department of Physics and Astronomy,
 University of Southampton, Highfield, Southampton SO17 1BJ, UNITED
 KINGDOM; telephone +44 1703 592058; telefax +44 1703 593910; e-mail
 <a href="mailto:sk@phys.soton.ac.uk">sk@phys.soton.ac.uk.</a> 74.60.Ge; 74.60.Jg; 74.72.Bk.
<p>
 Yeong-Lieh Lin and Franco Nori, "Quantum Interference in Superconducting
 Wire Networks and Josephson Junction Arrays: Analytical Approach Based
 on Multiple-Loop Aharonov-Bohm Feynman Path-Integrals." Department of
 Physics, West Virginia University, Morgantown, WV 26506-6315. 74.50.+r.
<p>
 A. N. Maljuk, A. A. Jokhov, I. G. Naumenko, I. K. Bdikin, S. A.
 Zver'kov, and G. A. Emel'chenko, "Growth and Characterization of Bulk
 Nd2-xCexCuO4 Single Crystals." To be published in Physica C (in press).
 Institute of Solid State Physics, Russian Academy of Sciences, 142432
 Chernogolovka, Moscow District, RUSSIA; telefax +7 096 576 4111; e-mail
 <a href="mailto:maluk@issp.ac.ru">maluk@issp.ac.ru.</a> Key words: Nd2-xCexCuO4, single-crystal growth,
 characterization, superconductivity.
<p>
 M. Meneghetti, "Dynamic Modulation of Electron Correlation by
 Intramolecular Modes in Charge Transfer Compounds." To be published in
 Phys. Rev. B. E-mail <a href="mailto:m.meneghetti@chfi.unipd.it">m.meneghetti@chfi.unipd.it,</a> preprint available at
 <a href="http://xxx.lanl.gov/abs/cond-mat/9911259">http://xxx.lanl.gov/abs/cond-mat/9911259.</a>
<p>
 A. Migliori, M. Gemmi, G. Calestani, D. Belletti, F. C. Matacotta, C.
 Dionigi, and P. Nozar, "Structure Determination by Electron Diffraction
 and HREM of the Incommensurate Modulated Phase BaxCuO2 (0.67 <= x <=
 0.70)." To be published in Physica C (in press). CNR Istituto LAMEL,
 Area della Ricerca di Bologna, via Gobetti 101, I-40129 Bologna, ITALY;
 telephone +39 051 639 9151; telefax +39 051 639 9216; e-mail
 <a href="mailto:migliori@lamel.bo.cnr.it">migliori@lamel.bo.cnr.it.</a> Key words: electron diffraction
 crystallography, crystal structure of inorganic compounds,
 incommensurate crystals, electron microscopy structure determination.
 61.66.Fn; 61.44.Fw; 61.16.Bg.
<p>
 A. J. Moreno and V. Bekeris, "ac Susceptibility in Deoxygenated YBCO
 Single Crystals." To be published in Physica C. Laboratorio de Bajas
 Temperaturas, Facultad de Ciencias Exactas y Naturales, Universidad
 Nacional de Buenos Aires, Ciudad Universitaria, Pabellon I, 1428 Buenos
 Aires, ARGENTINA; telefax +54 11 4576 3357; e-mail <a href="mailto:amoreno@df.uba.ar">amoreno@df.uba.ar;</a>
 preprint also available at <a href="http://xxx.lanl.gov/abs/cond-mat/9911149">http://xxx.lanl.gov/abs/cond-mat/9911149.</a>
 74.25.Ha; 74.60.Ge; 74.62.-c; 74.62.Dh; 74.72.Bk.
<p>
 Welles A. M. Morgado and Gilson Carneiro, "Numerical Method for Zero-
 Temperature Vortex-Line Phase Diagrams." To be published in Physica C
 (in press). Contact Gilson Carneiro, Instituto de Fisica, Universidade
 Federal do Rio de Janeiro, C.P. 68528, 21945-970 Rio de Janeiro, RJ,
 BRAZIL; telefax +55 21 290 9020; e-mail <a href="mailto:gmc@if.ufrj.br">gmc@if.ufrj.br;</a> preprint also
 available at <a href="http://xxx.lanl.gov/abs/cond-mat/9910336">http://xxx.lanl.gov/abs/cond-mat/9910336.</a> Key words:
 equilibrium vortex, zero-temperature phase diagram, type-II
 superconducting systems. 74.60.Ge; 74.60.-w.
<p>
 K. Nagashima, T. Otani, and M. Murakami, "Magnetic Interaction Between
 Permanent Magnets and Bulk Superconductors." To be published in Physica
 C (in press). Cryogenic Technology Laboratory, Maglev Systems
 Development Department, Railway Technical Research Institute, 2-8-38
 Hikari-cho, Kokubunji-shi, Tokyo 185-8540, JAPAN; telephone +81 42 573
 7301; telefax +81 42 573 7300; e-mail <a href="mailto:ken@rtri.or.jp">ken@rtri.or.jp.</a> Key words:
 electromagnetic force, permanent magnet, bulk superconductor, flywheel,
 Y-Ba-Cu-O. 74.25.Fy; 74.72.Bk; 74.80.Bj; 74.60.Jg.
<p>
 Michio Naito and Shin-ichi Karimoto, "New Superconducting Lead Cuprates
 Prepared by Molecular Beam Epitaxy." To be published in Adv. in
 Supercond XII: Proc. of the 12th Int. Symp. on Superconductivity
 (ISS'99), Morioka, Japan, Oct. 17-19, 1999. Superconducting Thin Film
 Research Group, NTT Basic Research Laboratories, 3-1 Morinosato-
 Wakamiya, Atsugi-shi, Kanagawa 243-01, JAPAN; telephone +81 462 40 3516;
 telefax +81 462 40 4717; e-mail <a href="mailto:michio@will.brl.ntt.co.jp">michio@will.brl.ntt.co.jp.</a> Key words:
 Pb-based superconductors, MBE, epitaxy, quasi-stable phase, low-
 temperature growth.
<p>
 Michio Naito, Hideki Yamamoto, and Hisashi Sato, "Intrinsic Problem of
 Cuprate Surface and Interface: Why Good Tunnel Junctions are Difficult
 to Fabricate." Presented at the 9th U.S.-Japan Workshop on High-Tc
 Supercond.; to appear in Physica C. Superconducting Thin Film Research
 Group, NTT Basic Research Laboratories, 3-1 Morinosato-Wakamiya, Atsugi-
 shi, Kanagawa 243-01, JAPAN; telephone +81 462 40 3516; telefax +81 462
 40 4717; e-mail <a href="mailto:michio@will.brl.ntt.co.jp">michio@will.brl.ntt.co.jp.</a>
<p>
 Tai Kai Ng, "Duality Picture Between Antiferromagnetism and d-Wave
 Superconductivity in t-J Model at Two Dimensions." Department of
 Physics, HKUST, Kowloon, Hong Kong, PEOPLE'S REPUBLIC OF CHINA; e-mail
 <a href="mailto:phtai@ust.hk">phtai@ust.hk;</a> preprint also available at <a href="http://xxx.lanl.gov/abs/cond-">http://xxx.lanl.gov/abs/cond-</a>
 mat/9911099. 74.20.Mn; 74.72.-h; 75.10.Jm.
<p>
 Terukazu Nishizaki, Tomoyuki Naito, Satoru Okayasu, Akihiro Iwase, and
 Norio Kobayashi, "Effects of Weak Point Disorder on the Vortex Matter
 Phase Diagram in Untwinned YBa2Cu3Oy Single Crystals." To be published
 in Phys. Rev. B. Institute for Materials Research, Tohoku University,
 Sendai 980-8577, JAPAN; telephone +81 22 215 2029; telefax +81 22 215
 2026; e-mail <a href="mailto:terukazu@imr.tohoku.ac.jp">terukazu@imr.tohoku.ac.jp.</a> 74.60.Ec; 74.60.Ge; 74.60.Jg;
 74.72.Bk.
<p>
 Franco Nori and C. Reichhardt, "Dynamic Phase Diagram and Orientational
 Dependence for Vortices in Superconductors with Periodic Arrays of
 Pinning Sites." Department of Physics, University of Michigan, Ann
 Arbor, MI 48109-1120; e-mail <a href="mailto:nori@umich.edu">nori@umich.edu.</a>
<p>
 M.T.D. Orlando, A. G. Cunha, S. L. Bud'ko, A. Sin, L. G. Martinez, W.
 Vanoni, H. Belich, X. Obradors, and E. Baggio-Saitovitch,
 "Hg0.95Re0.05Ba2Ca2Cu3O8+d Superconductor: Sample Preparation and
 Transport Properties Under Hydrostatic Pressure." To be published in
 Supercond. Sci. & Technol. Departamento de Fisica, Universidade Federal
 do Espirito Santo, Av. Fernando Ferrari, s/n, Vitoria-ES, 29060-900
 BRAZIL; telephone +55 27 3352482; telefax +55 27 3352823; e-mail
 <a href="mailto:orlando@cce.ufes.br">orlando@cce.ufes.br</a> or <a href="mailto:mtdazeredo@hotmail.com">mtdazeredo@hotmail.com.</a> Key words: synthesis of
 Hg, Re-1233, resistance under pressure, superconductivity. 74.62.Fj;
 74.62.Bf; 74.72.Gr.
<p>
 Y. Paltiel, E. Zeldov, Y. N. Myasoedov, H. Shtrikman, S. Bhattacharya,
 M. J. Higgins, Z. L. Xiao, E. Y. Andrei, P. L. Gammel, and D. J. Bishop,
 "Dynamic Instabilities and Memory Effects in Vortex Matter." To be
 published in Nature. Department of Condensed Matter Physics, Weizmann
 Institute of Science, Rehovot 76100, ISRAEL; telefax +972 8 934 4128; e-
 mail <a href="mailto:hpalt@wis.weizmann.ac.il">hpalt@wis.weizmann.ac.il.</a>
<p>
 C. Panagopoulos, J. R. Cooper, T. Xiang, Y. S. Wang, and C. W. Chu, "c-
 Axis Superfluid Response and Pseudogap in High-Tc Superconductors."
 Submitted to Phys. Rev. B. Interdisciplinary Research Centre in
 Superconductivity, University of Cambridge, Madingley Road, Cambridge
 CB3 0HE, UNITED KINGDOM; telephone +44 1223 337 072; telefax +44 1223
 337 074; e-mail <a href="mailto:cp200@hermes.cam.ac.uk">cp200@hermes.cam.ac.uk;</a> preprint also available at
 <a href="http://xxx.lanl.gov/abs/cond-mat/9911116">http://xxx.lanl.gov/abs/cond-mat/9911116.</a> 74.25.Nf; 74.62.Dh; 74.72.Dn;
 74.72.Gr.
<p>
 P. Piekarz and J. Konior, "Bismuth Cubic Superconductors: Polaronic and
 Superconducting Properties of the Rice-Sneddon Model." To be published
 in Physica C (in press). Contact J. Konior, Marian Smoluchowski
 Institute of Physics, Jagellonian University, ul. Reymonta 4, PL-30059
 Krakow, POLAND; e-mail <a href="mailto:konior@castor.if.uj.edu.pl">konior@castor.if.uj.edu.pl.</a> Key words:
 electron-doped superconductor, electron-phonon coupling, electronic
 structure, Hubbard model, phonon mechanism, polaronic superconductor.
 71.38.+i; 74.20.Fg; 74.20.-z; 74.72.-h.
<p>
 Y. Radzyner, A. Shaulov, and Y. Yeshurun, "Relaxation of the Remanent
 State in Thin Superconducting Samples." To be published in Physica B.
 Institute of Superconductivity, Department of Physics, Bar-Ilan
 University, Ramat Gan 52900, ISRAEL; e-mail <a href="mailto:radzyner@mail.biu.ac.il">radzyner@mail.biu.ac.il.</a>
 Key words: high temperature superconductors, magnetic relaxation,
 neutral line.
<p>
 A. P. Rassau, S. N. Gordeev, P.A.J. de Groot, R. Gagnon, and L.
 Taillefer, "Dynamic Stability of the Vortex Solid State of YBa2Cu3O7-d
 Single Crystals." To be published in Physica C (in press). Contact S.
 N. Gordeev, Department of Physics and Astronomy, University of
 Southampton, Highfield, Southampton SO17 1BJ, UNITED KINGDOM; telephone
 +44 1703 592058; telefax +44 1703 593910; e-mail <a href="mailto:sg@phys.soton.ac.uk">sg@phys.soton.ac.uk.</a>
 Key words: vortex dynamics, YBa2Cu3O7-d. 74.72.Bk; 74.60.Ge.
<p>
 G. Ravikumar, K. V. Bhagwat, V. C. Sahni, A. K. Grover, S. Ramakrishnan,
 and S. Bhattacharya, "A Phenomenological Model for History Effects and
 Metastability in Weakly Pinned Superconductors." Submitted to Phys.
 Rev. B. Technical Physics and Prototype Engineering Division, Bhabha
 Atomic Research Center, Mumbai 400 085, INDIA; e-mail
 <a href="mailto:gurazada@apsara.barc.ernet.in">gurazada@apsara.barc.ernet.in</a> or <a href="mailto:shobo@research.nj.nec.com">shobo@research.nj.nec.com.</a> 64.70.Dv;
 74.25.Ha; 74.60.Ge; 74.60.Jg.
<p>
 C. Reichhardt, C. J. Olson, and Franco Nori, "Dynamic Vortex Phases and
 Pinning in Superconductors with Twin Boundaries." To be published in
 Phys. Rev. B. Department of Physics, University of Michigan, Ann Arbor,
 MI 48109-1120; Franco Nori's e-mail <a href="mailto:nori@umich.edu">nori@umich.edu;</a> preprint also
 available at <a href="http://xxx.lanl.gov/abs/cond-mat/9910251">http://xxx.lanl.gov/abs/cond-mat/9910251.</a> 74.60.Ge.
<p>
 E. J. Romans, P.A.C. Tavares, and C. M. Pegrum, "Behavior of HTS
 Josephson Vortex Flow Transistors." To be published in Physica C (in
 press). Department of Physics and Applied Physics, University of
 Strathclyde, Rottenrow, Glasgow G4 0NG, UNITED KINGDOM; telephone +44
 141 548 3478; telefax +44 141 552 2891; e-mail <a href="mailto:cabs34@strath.ac.uk">cabs34@strath.ac.uk.</a> Key
 words: superconducting devices, three-terminal devices. 85.25.Am.
<p>
 M.J.R. Sandim and R. F. Jardim, "Intergranular Transport Properties of
 Polycrystalline Sm1.82Ce0.18CuO4-y Under Low Applied Magnetic Fields."
 To be published in Physica C (in press). Contact R. F. Jardim,
 Departamento de Engenharia de Materiais, Faculdade de Engenharia Quimica
 de Lorena, CP 116, 12600-000 Lorena, SP, BRAZIL; telephone +55 11 818
 6896; telefax +55 11 818 6984; e-mail <a href="mailto:rjardim@if.usp.br">rjardim@if.usp.br.</a> Key words:
 granular superconductors, Josephson coupling, intergranular critical
 current. 74.50.+r; 74.60.Jg; 74.80.Bj.
<p>
 F. Sandiumenge, T. Puig, J. Rabier, J. Plain, and X. Obradors,
 "Optimization of Flux Pinning in Bulk Melt Textured 1-2-3
 Superconductors: Bringing Dislocations Under Control." Submitted to
 Adv. Mater. Institut de Ciencia de Materials de Barcelona, CSIC, Campus
 de la Universitat Autonoma de Barcelona, E-08193 Bellaterra, Catalonia,
 SPAIN; e-mail <a href="mailto:felip@icmab.es">felip@icmab.es.</a>
<p>
 K. Schlenga, R. McDermott, John Clarke, R. E. de Souza, A. Wong-Foy, and
 A. Pines, "Low-Field Magnetic Resonance Imaging with a High-Tc dc
 Superconducting Quantum Interference Device." To be published in Appl.
 Phys. Lett. Contact R. McDermott, Department of Physics, 366 LeConte
 Hall, University of California, Berkeley, CA 94720; telephone (510) 642-
 3634; telefax (510) 642-1304; e-mail <a href="mailto:rmcderm@socrates.berkeley.edu">rmcderm@socrates.berkeley.edu.</a> Key
 words: SQUID, NMR, MRI. 85.25.Dq; 76.60.Pc; 07.55.Ge.
<p>
 A. Shelankov and M. Ozana, "Quasiclassical Theory of Superconductivity:
 A Multiple Interface Geometry." Department of Theoretical Physics, Umea
 University, 901 87 Umea, SWEDEN; e-mail <a href="mailto:andrei.shelankov@tp.umu.se">andrei.shelankov@tp.umu.se;</a>
 preprint also available at <a href="http://xxx.lanl.gov/abs/cond-mat/9907230">http://xxx.lanl.gov/abs/cond-mat/9907230.</a>
 74.20.Fg; 74.50.+r; 74.80.Dm; 74.80.Fp.
<p>
 E. Sheriff, D. Giller, Y. Radzyner, A. Shaulov, Y. Schlesinger, and Y.
 Yeshurun, "Distribution of Induction, Electric Field, and Current
 Density in Thin YBa2Cu3O7-x Films Carrying Transport Current."
 Institute of Superconductivity, Department of Physics, Bar-Ilan
 University, Ramat Gan 52900, ISRAEL; telephone +972 3 531 8607; telefax
 +972 3 535 3298. 74.76.Bz; 74.60.Ge.
<p>
 Masahiro Sugimoto, Akira Takagi, Masanao Mimura, Shoichi Honjo, Tomoo
 Mimura, and Yoshihiro Iwata, "ac Losses to be Reduced by Twisting
 Filaments in a Silver-Sheathed Bi-2223 Multifilamentary Tape." To be
 published in Physica C (in press). Superconductivity Research
 Department, The Furukawa Electric, Kiyotaki 500, Nikko, Tochigi 321-
 1493, JAPAN; telephone +81 288 54 0505; telefax +81 288 54 2216; e-mail
 <a href="mailto:masahiro@nikko.furukawa.co.jp">masahiro@nikko.furukawa.co.jp.</a> Key words: applications of high-Tc
 superconductors, ac losses, magnetization, granular superconductivity.
 74.25.Ha; 74.72.-h; 74.20.-z.
<p>
 M. D. Sumption, R. M. Scanlan, A. Nijhuis, and E. W. Collings, "ac Loss
 and Contact Resistance In Copper-Stabilized Nb3Al Rutherford Cables With
 and Without a Stainless Steel Core." E-mail <a href="mailto:sumption@mse.eng.ohio-">sumption@mse.eng.ohio-</a>
 state.edu, preprint available at <a href="http://xxx.lanl.gov/abs/cond-">http://xxx.lanl.gov/abs/cond-</a>
 mat/9911191.
<p>
 T. Takayanagi, T. Kitajima, T. Takemura, and I. Terasaki, "Anisotropic
 Dielectric Constant of the Parent Antiferromagnet Bi2Sr2MCu2O8 (M = Dy,
 Y and Er) Single Crystals." Submitted to the Proc. of the 12th Int.
 Symp. on Superconductivity (ISS'99), Morioka, Japan, Oct. 17-19, 1999.
 Department of Applied Physics, Waseda University, Tokyo 169-8555, JAPAN;
 I. Terasaki's e-mail <a href="mailto:terra@mn.waseda.ac.jp">terra@mn.waseda.ac.jp.</a> Key words: parent
 antiferromagnet, dielectric constant, insulator-metal transition.
<p>
 J. L. Tallon, J. W. Loram, G.V.M. Williams, and C. Bernhard, "Heat
 Capacity and Transport Studies of the Ferromagnetic Superconductor
 RuSr2GdCu2O8." Submitted to Phys. Rev. Lett. E-mail
 <a href="mailto:j.tallon@irl.cri.nz">j.tallon@irl.cri.nz,</a> preprint available at <a href="http://xxx.lanl.gov/abs/cond-">http://xxx.lanl.gov/abs/cond-</a>
 mat/9911136.
<p>
 P. Tarasewicz and J. Mackowiak, "Thermodynamic Functions of Fermi Gas
 with Quadruple BCS-Type Binding Potential." To be published in Physica
 C (in press). Institute of Physics, N. Copernicus University, ul.
 Grudziadzka 5/7, PL 87-100 Torun, POLAND; telephone +48 56 611 3310;
 telefax +48 56 622 5397; e-mail <a href="mailto:tarasek@phys.uni.torun.pl">tarasek@phys.uni.torun.pl.</a> Key words:
 superconductivity, BCS-type interaction, fermion pairs, fermion
 quadruples, infinite-volume limit.
<p>
 G. B. Teitel'baum, B. Buechner, and H. de Gronckel, "The Cu NQR Study of
 the Stripe Phase Local Structure in the Lanthanum Cuprates." Institute
 for Technical Physics, 420029 Kazan, RUSSIA; e-mail
 <a href="mailto:teitelbaum@phys.leidenuniv.nl">teitelbaum@phys.leidenuniv.nl;</a> preprint also available at
 <a href="http://xxx.lanl.gov/abs/cond-mat/9910036">http://xxx.lanl.gov/abs/cond-mat/9910036.</a>
<p>
 I. Terasaki, T. Takemura, T. Takayanagi, and T. Kitajima, "Anomalous
 Charge Transport of the Parent Antiferromagnet Bi2Sr2RCu2O8." Submitted
 to the Proc. of the 12th Int. Symp. on Superconductivity (ISS'99),
 Morioka, Japan, Oct. 17-19, 1999. Department of Applied Physics, Waseda
 University, Tokyo 169-8555, JAPAN; e-mail <a href="mailto:terra@mn.waseda.ac.jp">terra@mn.waseda.ac.jp;</a>
 preprint also available at <a href="http://xxx.lanl.gov/abs/cond-mat/9911153">http://xxx.lanl.gov/abs/cond-mat/9911153.</a>
 Key words: parent antiferromagnet insulator, confinement, pseudogap.
<p>
 M. R. Trunin, Yu. A. Nefyodov, and Herman J. Fink, "Phenomenological
 Description of the Microwave Surface Impedance and Complex Conductivity
 of High-Tc Single Crystals." Institute of Solid State Physics, 142432
 Chernogolovka, Moscow District, RUSSIA; e-mail <a href="mailto:nefyodov@issp.ac.ru">nefyodov@issp.ac.ru;</a>
 preprint also available at <a href="http://xxx.lanl.gov/abs/cond-mat/9911211">http://xxx.lanl.gov/abs/cond-mat/9911211.</a>
<p>
 V. I. Tsebro, O. E. Omel'yanovskii, and A. P. Moravskii, "Persistent
 Currents and Magnetic Flux Trapping in Fragments of Carbon Deposits
 Containing Multiwalled Nanotubes." To be published in JETP Lett. P. N.
 Lebedev Physics Institute, Russian Academy of Sciences, 117924 Moscow,
 RUSSIA; e-mail <a href="mailto:tsebro@sci.lebedev.ru">tsebro@sci.lebedev.ru;</a> preprint also available at
 <a href="http://xxx.lanl.gov/abs/cond-mat/9911432">http://xxx.lanl.gov/abs/cond-mat/9911432.</a> 81.05.Ys; 73.23.Ra.
<p>
 J. F. Wambaugh, C. Reichhardt, C. J. Olson, F. Marchesoni, and Franco
 Nori, "Superconducting Fluxon Pumps and Lenses." To be published in
 Phys. Rev. Lett. Contact Franco Nori, Department of Physics, University
 of Michigan, Ann Arbor, MI 48109-1120; e-mail <a href="mailto:nori@umich.edu">nori@umich.edu;</a> preprint
 also available at <a href="http://xxx.lanl.gov/abs/cond-mat/9910484">http://xxx.lanl.gov/abs/cond-mat/9910484.</a> 05.40.-a;
 74.60.Ge; 05.60.-k.
<p>
 Yi-Yuan Xie, Judy Z. Wu, Shaolin Yan, Yang Yu, Tolga Aytug, Lang Fang,
 and S. C. Tidrow, "Elimination of Air Detrimental Effect Using Tl-
 Stabilized Precursor for Epitaxial HgBa2CaCu2O6 Thin Films." To be
 published in Physica C (in press). Department of Physics and Astronomy,
 University of Kansas, 1082 Mallot Hall, Lawrence, KS 66045; e-mail
 <a href="mailto:yyxie@eagle.cc.ukans.edu">yyxie@eagle.cc.ukans.edu.</a> Key words: high-temperature
 superconductivity, Hg-1212, thin films, thallium. 74.72.Gr; 74.76.Bz;
 74.62.Bf; 74.60.Jg.
<p>
 K. Yamafuji, F. Fujiyoshi, T. Kiss, M. Inoue, T. Sasaki, and N.
 Kobayashi, "The Nernst Effect in High-Tc Cuprate Superconductors." To
 be published in Physica C (in press). Ariake National College of
 Technology, 150 Higashihagio-machi, Omuta 836-8585, JAPAN; telephone +81
 944 53 8601; telefax +81 944 53 1361; e-mail <a href="mailto:yamafuji@ariake-nct.ac.jp">yamafuji@ariake-nct.ac.jp.</a>
 Key words: high-Tc superconductors, Nernst effect, resistive
 transition, flux pinning, transport entropy, thermal fluctuation.
<p>
 Hideki Yamamoto, Michio Naito, and Hisashi Sato, "A New Superconducting
 Barium Cuprate Prepared by Molecular Beam Epitaxy." Presented at 5th
 Int. Workshop on Chemical Designing and Processing of High-Tc Supercond.
 (Chem-HTSC V); to be published in Physica C. NTT Basic Research
 Laboratories, 3-1 Morinosato-Wakamiya, Atsugi-shi, Kanagawa 243-0198,
 JAPAN; Michio Naito's telephone +81 462 40 3516; telefax +81 462 40
 4717; e-mail <a href="mailto:michio@will.brl.ntt.co.jp">michio@will.brl.ntt.co.jp.</a> Key words: new superconductor,
 MBE, contamination-free environment, ozone oxidation, Ba2CuO3, Ba2CuO4-
 d.
<p>
 Kun Yang and S. L. Sondhi, "Zeeman and Orbital Effects of an in-Plane
 Magnetic Field in Cuprate Superconductors." National High Magnetic
 Field Laboratory and Department of Physics, Florida State University,
 Tallahassee, FL 32310; e-mail <a href="mailto:kunyang@magnet.fsu.edu">kunyang@magnet.fsu.edu;</a> preprint also
 available at <a href="http://xxx.lanl.gov/abs/cond-mat/9910418">http://xxx.lanl.gov/abs/cond-mat/9910418.</a>
<p>
 Mina Yoon, M. Y. Choi, and Beom Jun Kim, "Lattice Effects on the
 Current-Voltage Characteristics of Superconducting Arrays." To be
 published in Phys. Rev. B. Department of Physics and Center for
 Theoretical Physics, Seoul National University, Seoul 151-742, KOREA;
 Beom Jun Kim's e-mail at Umea University <a href="mailto:kim@tp.umu.se">kim@tp.umu.se;</a> preprint also
 available at <a href="http://xxx.lanl.gov/abs/cond-mat/9911236">http://xxx.lanl.gov/abs/cond-mat/9911236.</a> 74.50.+r;
 74.25.Fy; 74.60.Ge.
<p>
 K. N. Yugay, N. V. Blinov, and I. V. Shirokov, "Flux Quantization, Chaos
 and State Stability in Long Josephson Junctions." Submitted to J. Low
 Temp. Phys. Omsk State University, 55a Prospect Mira, 644055 Omsk,
 RUSSIA; telephone +7 3812 22 5673; telefax +7 3812 64 1201; e-mail
 <a href="mailto:yugay@phys.omsu.omskreg.ru">yugay@phys.omsu.omskreg.ru.</a> 05.45.+b; 74.50.+r.
<p>
 H. W. Zandbergen, J. Jansen, V. L. Svetchnikov, I. E. Graboy, S.
 Samoylenkov, O. Gorbenko, and A. R. Kaul, "The Structure of BaCu3O4
 Particles Occurring on Thin HoBa2Cu3O7 Films Prepared by MOCVD." To be
 published in Physica C (in press). National Centre for HREM, Laboratory
 of Materials Science, Delft University of Technology, Rotterdamseweg
 137, Delft 2628 AL, THE NETHERLANDS; telephone +31 15 278 2266; telefax
 +31 15 278 6730; e-mail <a href="mailto:zandbergen@stm.tudelft.nl">zandbergen@stm.tudelft.nl.</a> Key words: BaCu3O4,
 HoBa2Cu3O7, MOCVD.
 <hr>
<p>
<p>
 COMING EVENTS
 (An * indicates a previously listed event. Also see complete listing of
 upcoming conferences and workshops at our Web site
 <a href="http://www.iitap.iastate.edu/htcu/comevents.html.)">http://www.iitap.iastate.edu/htcu/comevents.html.)</a>
<p>
 Feb. 17 - 22, 2000: The 2000 AAAS Annual Meeting and Science Innovation
 Exposition -- Science in an Uncertain Millenium, Washington Marriott
 Wardman Park and the Omni Shoreham, Washington, D.C. The 166th national
 meeting of AAAS will bring together more than 5,000 scientists,
 engineers, educators, policy-makers, and researchers in a
 multidisciplinary forum to share the latest research advances.
 Abstracts solicited for contributed poster presentations. The Meeting
 will feature more than 150 scientific symposia; specialized seminars;
 topical, plenary, and award lectures; poster sessions; an exhibition
 hall; field trips; career workshops; and a science career fair. Poster
 sessions are an important way for individuals to participate at the AAAS
 meeting. Abstract deadline, January 7, 2000. Symposia topics are:
 changing landscapes; communicating science; education and public
 understanding of science; environment, food, and natural resources;
 global change/earth systems science; human futures; industry and
 engineering; interconnectivity and life in cyberspace; life science and
 the science of life; looking back to forecast the future; looking beyond
 earth; mathematics and physical science; natural history in the new
 millennium; public health and medicine; science and society; science,
 engineering, and public policy; and science innovation. AAAS Meetings
 Office, 1200 New York Avenue NW, Washington DC 20005; telephone (202)
 326-6450; telefax (202) 289-4021; e-mail <a href="mailto:confinfo@aaas.org">confinfo@aaas.org.</a>
<p>
 March 12 - 16, 2000: 129th Annual Meeting & Exhibition of The Minerals,
 Metals & Materials Society,TMS Annual Meeting, Nashville, Tenn. More
 than 4,000 science and engineering professionals representing over 70
 different countries will come together at this meeting. At least 200
 sessions and 1,000 individual presentations. Technical areas of
 interest include precious metal extraction, aluminum processing, high-
 temperature superconductors, and many other materials fields and
 metallurgical disciplines. This year's meeting will feature programming
 by the Electronic, Magnetic & Photonic Materials Division, Extraction &
 Processing Division, Light Metals Division, Materials Processing &
 Manufacturing Division, Structural Materials Division, TMS Education
 Committee, TMS Young Leaders Committee, and Materials Science Critical
 Technologies Sector of ASM International. For information, contact TMS
 Meetings Services, 184 Thorn Hill Road, Warrendale, PA 15086; telephone
 (724) 776-9000, ext. 243; telefax (724) 776-3770; e-mail
 <a href="mailto:mtgserv@tms.org">mtgserv@tms.org.</a>
<p>
 *March 20 - 24, 2000: 2000 March Meeting, Minneapolis Convention
 Center, Minneapolis, Minn. Sessions on superconductivity will include
 the following topics: synthesis, growth, and processing (bulk and
 films); thermodynamic and transport properties; mechanical and
 structural properties; electronic structure and spectroscopic
 properties; flux pinning and flux dynamics; spin properties (NMR, NQR,
 etc.); tunnel junctions, devices, and Josephson arrays; quantum
 computing; and other focused sessions. For further general information,
 contact Donna Baudrau, Manager, APS Meetings Department, telephone (301)
 209-3285, e-mail <a href="mailto:baudrau@aps.org">baudrau@aps.org;</a> more information on the March meeting
 is available at the Web site <a href="http://www.aps.org/meet/MAR00/">http://www.aps.org/meet/MAR00/.</a>
<p>
 *March 31 - April 10, 2000: Conference on Major Trends in
 Superconductivity in the New Millennium (MTSC 2000) and Symposium on
 Itinerant and Localized States in HTSC (SILS), Klosters, Kanton
 Graubuenden, Switzerland. Scope of MTSC 2000 is on recent developments
 and trends in new superconducting systems with emphasis on experiments
 and theories which are relevant to the pairing mechanism. Besides the
 superconducting cuprates, conventional superconductors, organic systems,
 borocarbides, ruthenates, nanostructures, and fullerenes will be
 addressed. In order to raise the awareness for novel ideas and results
 in this rapidly growing field, the physics and chemistry of related
 materials will be included. Special emphasis on phenomena related to
 nanoscale phase separation and charge modulation. Symposium on
 Itinerant and Localized States in HTSC (SILS) will focus on large and
 small polaron and bipolaron effects in high-Tc materials with special
 emphasis on their preparative properties. MTSC 2000 is organized in
 close analogy to the Gordon conferences. Total number of participants
 limited to 130 persons. Proceedings will be published in a special
 issue of Journal of Superconductivity. For more information, contact
 Annette Bussmann-Holder, Max-Planck-Institut fuer Festkoerperforschung,
 Heisenbergstr. 1, D-70569 Stuttgart, Germany; telephone +49 711 689
 1679; telefax +49 711 689 1091. Or contact Vladimir Z. Kresin, Lawrence
 Berkeley Laboratory, University of California, 1 Cyclotron Road,
 Berkeley CA 94720; telephone (510) 486-6951; telefax (510) 486-5401.
 Information also available at Web site <a href="http://www.mpi-">http://www.mpi-</a>
 stuttgart.mpg.de/CONF/mtsc2000.html.
<p>
 June 19 - 22, 2000: International Workshop on Superconductivity,
 Kunibiki Messe, Matsue, Shimane Prefecture, Japan. Workshop will focus
 on fundamental properties of high-temperature superconducting materials
 for actual applications. Theme of the workshop is "Structure and
 Property Relationships for Applications of High-Temperature
 Superconducting Materials." No parallel sessions; significant amount of
 time to be allotted for the discussion of each paper. Topics of
 interest (including, but not restricted to): interfaces, grain
 boundaries, surfaces, thin films, bulks, wires and tapes, etc. Invited
 presentations, contributed papers, and contributed posters. One-page
 summary deadline, January 15, 2000. Contact Tetsuji Kobayashi,
 Director, International Affairs Department, ISTEC Eishin Kaihatsu Bldg.,
 6F, 34-3 Shimbashi 5-chome, Minato-ku, Tokyo 105-0004, Japan; telephone
 +81 3-3431 4002; telefax +81 3 3431 4044; e-mail t-
 <a href="mailto:kobayashi@istec.or.jp">kobayashi@istec.or.jp;</a> Web page
 <a href="http://www.istec.or.jp/ISTEC_homepage/WORK/e-workshop.html">http://www.istec.or.jp/ISTEC_homepage/WORK/e-workshop.html.</a>
<p>
 *June 21 - 23, 2000: 4th European Workshop on Low Temperature
 Electronics (WOLTE-4), European Space Research and Technology Centre
 (ESTEC), Noordwijk, The Netherlands. Organized by the European Space
 Agency (ESA) and co-sponsored by IEEE/EDS. Objective of the workshop is
 to provide an international forum for discussing recent research and
 development in the area of low-temperature electronics including
 semiconductors, low- and high-temperature superconductors, devices,
 circuits, and systems. Emphasis on the application of these for space
 instrumentation. Both oral and poster presentations. Intent to exhibit
 or to organize a short course should be indicated to the Conference
 Secretariat with a preliminary description of requirements by October
 15, 1999. Topics: device physics and fundamental aspects, fabrication
 technologies, device and circuit design, packaging and interconnections,
 front-end systems for cryogenic sensors, device simulation and modeling,
 cryogenic measurements and instrumentation, new materials and novel
 technologies, space-related applications, refrigeration, and interfacing
 for electronics. Abstract deadline, December 15, 1999. Contact ESTEC
 Conference Bureau, P.O. Box 299, 2200 AG Noordwijk, The Netherlands;
 telephone +31 71 5655005; telefax +31 71 5655658; e-mail
 <a href="mailto:confburo@estec.esa.nl">confburo@estec.esa.nl;</a> Web site
 <a href="http://www.estec.esa.nl/CONFANNOUN/wolte4/">http://www.estec.esa.nl/CONFANNOUN/wolte4/.</a>
<p>
 July 23 - 25, 2000: International Symposium on Local Lattice
 Distortions (LLD2K), AIST Tsukuba Research Center, Ibaraki, Japan.
 Intensive discussions on physics related to local lattice distortions,
 with the aim of establishing its role in exotic properties of strongly
 correlated systems such as high-Tc superconductivity, colossal
 magnetoresistance, and related topics. Topics include local lattice
 distortions associated with stripes, charge and orbital ordering,
 lattice anomalies, phase transitions, excited states, and impurities.
 For further information, contact LLD2K Secretariat, Electrotechnical
 Laboratory, 1-1-4 Umezono, Tsukuba, Ibaraki, 305-8568, Japan; telephone
 +81 298 54 5072; telefax +81 298 54 5085; e-mail <a href="mailto:lld2k@etl.go.jp">lld2k@etl.go.jp;</a> Web
 site <a href="http://www.etl.go.jp/~lld2k/">http://www.etl.go.jp/~lld2k/.</a>
<p>
 *Sept. 13 - 16, 2000: The Second International Conference on Inorganic
 Materials, University of California, Santa Barbara. Meeting will
 provide an opportunity to highlight recent developments and to identify
 emerging and future areas of growth in this field. Topics include
 electronic materials, structural materials and ceramics, biomaterials,
 intermetallics, catalytic and porous materials. Emphasis on oral
 presentations by invited speakers combined with extended poster
 sessions. Abstract deadline, February 25, 2000. Official language is
 English. A tabletop exhibition will run for the duration of the
 conference. For information, contact Sarah Wilkinson, Second
 International Conference on Inorganic Materials, Elsevier Science Ltd.,
 The Boulevard, Langford Lane, Kidlington, Oxford, OX5 1GB, United
 Kingdom; telephone +44 1865 843691; telefax +44 1865 843958; e-mail
 <a href="mailto:sm.wilkinson@elsevier.co.uk">sm.wilkinson@elsevier.co.uk.</a>
 <hr>
<p>
 RESOURCES
<p>
 Information
<p>
 Proceedings: The European Conference on Energy Dispersive X-ray
 Spectrometry (EDXRS-98), Bologna, Italy, June 7-12, 1998, edited by J.
 E. Fernandez and A. Tartari. A selection of the papers presented at
 EDXRS-98 has been arranged in ten topical sections which reflect the
 true distribution of the contributions and consequently the academic
 interest of the participants. Section I -- Interaction of Photons and
 Particles with Matter and their Modeling; Section II -- Energy
 Dispersive X-ray Detectors, is devoted to the rapidly changing field of
 photon detectors; Section III -- X-ray Optics, TXRF, and Capillarity,
 shows the state-of-art of optical techniques for x-rays; Section IV --
 Instrumentation, is devoted to novel instrumental solutions in x-ray
 spectrometry; Section V -- Microanalysis, is devoted to particle and
 photon microprobes; Section VI -- Applications to Medicine, opens the
 applications part of the volume with the medical applications of x-ray
 spectrometry; Section VII -- Applications to Biology, concerns primarily
 applications in botany; Section VIII -- Applications in Environmental
 Research, is devoted to a sector where trace element techniques play an
 important role; Section IX -- Applications to Archaeometry, groups the
 presentations in a field sensitive to the nondestructive capability of
 spectrometrical quantitation; and Section X -- Applications to Industry,
 reveals the growing role of x-ray spectrometry in industrial technology.
 Publ. 1999; 366 pp.; price Lit. 170,000; ISBN 88-7794-195-2. For order
 information, contact Editrice Compositori, Via Stalingrado 97/2, 40128
 Bologna, Italy; telefax +39 051 327877.
<p>
 <hr>
<p>
 High-Tc Update is the high-Tc superconductivity information exchange
 newsletter. Please send 1) preprints, reprints, and other research
 reports; 2) descriptions of on-going work; 3) meeting announcements and
 summaries.
<p>
 The information contained herein is intended for limited distribution.
 Readers are expected to respect the rights of the authors.
<p>
 Please address all contributions and inquiries to:
 Dr. Sreeparna Mitra, A219 Physics
 Ames Laboratory/Iowa State University
 Ames, Iowa 50011-3020
 Telephone: (515) 294-3877 Telefax: (515) 294-1134
 E-mail: <a href="mailto:MITRA@AMESLAB.GOV">MITRA@AMESLAB.GOV</a>
 or <a href="mailto:MITRA@IASTATE.EDU">MITRA@IASTATE.EDU</a>
<p>
 Project Director/Editor: Sreeparna Mitra
 Science Editor: John R. Clem
 High-Tc Update, Vol. 13, #24, December 15, 1999.
 <hr>