Published for the Division of Materials Sciences, Office of Basic Energy Sciences, USDOE, under Contract W-7405-eng-82 with the Ames Laboratory,Iowa State University. Funded by DMS/BES/USDOE, ARPA, and other agencies, organizations, and individuals.

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 MITRA@AMESLAB.GOV or MITRA@IASTATE.EDU.

The High-Tc Update web page is located at the URL http://www.iitap.iastate.edu/htcu/htcu.html

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.

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).

NOTA BENE:

READERS: Please remember that the main purpose of the newsletter is to make information available about PREPRINTS, not REPRINTS. It would be greatly appreciated, therefore, if you would send us your manuscripts as early as possible so that they are not already published by the time we list them. Thanks!

RBa2Cu3O7-d

Measurements by Y. Ando (CRIEPI) et al. of the in-plane magnetoresistance of heavily underdoped, nonsuperconducting, antiferromagnetic YBa2Cu3O6+x (x = 0.30 and 0.32) have revealed novel behavior that unveils a well-developed charged-stripe structure in this system. One of the striking features is magnetoresistance anisotropy with d-wave symmetry upon rotating the magnetic field H within the ab plane.other features are anomalous behavior of the magnetoresistance at low magnetic fields and saturation above a well-defined threshold field, as well as hysteretic behavior at low temperatures. The authors show that the overall features can be consistently explained by assuming a well-developed array of charged stripes and a field-induced topological ordering of the stripes. At temperatures below ~10 K, an external field of the order of a few T can produce a persistent directional ordering of the stripes, giving rise to a memory effect in the resistivity. The authors conclude that charge inhomogeneities in the CuO2 planes in the form of stripes exist and that they have a considerable impact on the electron transport. The data also show that the magnetic field can be used as a tool to manipulate the striped structure.

The low-energy electronic excitation spectrum and gap structure in optimally doped and overdoped Y1-xCaxBa2Cu3O7-d single crystals have been investigated by J. Demsar (Ljubljana) et al. using real-time measurements of the quasiparticle relaxation dynamics via femtosecond optical spectroscopy. From the amplitude of the photoinduced reflectivity as a function of time, temperature, and doping x, the authors find evidence for the coexistence of two distinct gaps in the entire overdoped phase. One is a temperature-independent pseudogap Delta_p, and the other is a T-dependent collective gap Delta_c(T), which has a BCS-like T dependence, closing at Tc. From quasiparticle relaxation-time measurements above Tc, the authors ascertain that fluctuations associated with the collective gap Delta_c(T) are limited to a few K, consistent with time-dependent Ginzburg-Landau theory, and are unrelated to the pseudogap, whose presence is apparent well above Tc for all x.

The optical conductivity sigma(omega) of undoped YBa2Cu3O6 has been studied by M. Grueninger (Groningen) et al. in the mid-infrared (MIR) range. The authors made substitutions on all but the Ba site to identify the prominent absorption processes at 2800 cm^[-1] and 3800 cm^[-1], and they collected experimental evidence for bimagnon-plus-phonon absorption. The authors find that existing spin-wave theory is incapable of explaining both MIR and Raman data, and they suggest that only a treatment accounting for short-wavelength magnetic excitations will be able to explain the observed anomalies.

Reversible properties of the remanent magnetic moment M_[rem] in superconducting submicron- and micron-size YBCO particles and thin films have been investigated by E. V. Blinov (St. Petersburg) et al. using a SQUID magnetometer. In micron-size particles and thin films, the authors observed a monotonic increase of M_[rem] as the temperature decreased. In submicron particles, the same monotonic behavior was observed at first, but at the lowest temperatures an unusual reentrant behavior was found: M_[rem] decreased when the sample was cooled below 6 K. This phenomenon was found to be independent of the direction of the thermal cycle. The authors discuss possible mechanisms for this effect, including midgap states in the quasiparticle excitation spectrum and defect-induced localization of Cooper pairs.

Bi Cuprates

Heavy Pb doping has been shown to produce large enhancements of both the irreversibility field H_[irr] and the critical current density Jc of Bi2Sr2CaCu2O8+d (Bi-2212). To investigate the possibility that this effect is due to the reduced electromagnetic anisotropy caused by Pb doping, T. Motohashi et al. (Tokyo) have carried out measurements of the out-of-plane resistivity (rho_c) and in-plane resistivities (rho_a and rho_b) of Bi2.1-xPbxSr1.8CaCu2O8+d single crystals with various Pb content (0 <= x <= 0.6). The authors found that the absolute value of rho_c in the normal state systematically decreased with increasing Pb content, whereas no appreciable change was observed in rho_a and rho_b. The resistivity anisotropy parameter gamma^2 == rho_c/rho_[ab] = rho_c/(rho_arho_b)^[1/2] at 100 K was found to be 8.5 x 10^3, 2.5 x 10^3, and 1.2 x 10^3 for oxygen-overdoped crystals with x = 0, 0.3, and 0.6, respectively. These results suggest that the electrical conductivity of the blocking layers is systematically enhanced by Pb doping, leading to a large reduction of the resistivity anisotropy in this compound.

A preprint by R. Funahashi (Osaka National Research Institute) et al. reports the properties of heavily Pb-doped Bi-2212/Ag tapes prepared using an isothermal partial melting method. For the composition

As noted by K. Kwasnitza (PSI-Villigen) et al., flat high-Tc Bi-2223/Ag multifilamentary tapes with a silver matrix have large coupling-current losses in the worst case of perpendicularly applied 50 Hz magnetic fields. The authors report that by surrounding twisted superconducting filaments (twist length 2 cm) by ceramic, nearly insulating BaZrO3 and SrZrO3 barriers, they could reduce the coupling-current-decay time constant to 1.5 ms at 77 K, leading to a significant loss reduction at 25 Hz and a noticeable loss reduction at 50 Hz. For small Delta[B] values, the coupling-loss maximum was shifted to 110 Hz for a stack of six tapes and to 180 Hz for a single tape. The authors are optimistic that additional loss-reduction techniques (reduction of the aspect ratio to less than 8, reduction of the twist length to less than 1 cm, and further increase of the transverse resistivity) soon will make it possible to fabricate high-Tc conductors with low 50 Hz magnetic field losses at Delta[B]_[perp.] >= 0.2 T.

Other Cuprates

Epitaxial thin films of the Tl cuprate superconductors Tl2Ba2CaCu2O8+d (Tl-2212), Tl2Ba2Ca2Cu3O10 (Tl-2223), and Tl0.78Bi0.22Ba0.4Sr1.6Ca2Cu3O10 [(Tl,Bi)-1223] have been studied by R.P. Vasquez (JPL) et al. using x-ray photoemission spectroscopy. In Cu 2p spectra, a larger energy separation between the satellite and main peaks (E_s - E_m) and a lower intensity ratio (I_s/I_m) were found to correlate with higher values of Tc. For samples near optimum doping, maximum Tc is reported to occur when the Tl 4f_[7/2] binding energy is near 117.9 eV, near the middle of the range of values observed for Tl cuprates.

Copper NQR experiments in the high-temperature superconductors YBa2Cu4O8, YBa2Cu3O7, and La2-xSrxCuO4 (x = 0.12 and x = 0.15) have been performed by S. Fujiyama (ISSP-Tokyo) et al. using the stimulated echo technique with the rf pulse sequence pi/2 - (tau) - pi/2 - (T - tau) - pi/2. The authors analyze the tau and T dependencies of the stimulated echo intensity using a model that includes the spin-lattice relaxation process (T_1 process) and the fluctuating local field due to nuclear spin-spin coupling. The model gives a quantitative account of the experimental results in YBa2Cu4O8 and YBa2Cu3O7, using the known values of 1/T_1 and 1/T_[2G], the gaussian decay rate of the spin-echo intensity. The same model applied to La2-xSrxCuO4 enabled the authors to extract the value of T_[2G] for this material. The authors found that T_1T/T_[2G] is independent of temperature, indicating that the dynamic exponent z = 1 in La2-xSrxCuO4.

Superstructure reflections due to the ordering of holes into stripes in La1.45Nd0.4Sr0.15CuO4 have been studied by T. Niemoeller (HASYLAB) et al. using high-energy x-ray diffraction. These reflections have been observed clearly for the first time in a sample that is superconducting at low temperatures (Tc ~ 10 K). The stripe peaks vanish above 62(5) K, whereas the magnetic signal of the stripe ordering, which has been seen with neutrons previously, is already suppressed at ~45 K. The results confirm that the ordering of spins and holes is driven by the charges, as found in the case of La1.6-xNd0.4SrxCuO4 at the doping level of x = 0.12.

Sr2RuO4

Though with a Tc less than 1.5 K it is certainly not a high-temperature superconductor, Sr2RuO4 has attracted considerable attention because of its many unusual properties. The data suggest that (a) this layered perovskite is an essentially two-dimensional Fermi liquid in the normal state but there are strong correlations among electrons, (b) Sr2RuO4 is close to a ferromagnetic instability, which suppresses s- and d-wave superconductivity, and (c) Sr2RuO4 in the superconducting state is a triplet p-wave superconductor.

As reported by Y. Sidis (Laboratoire Leon Brillouin, Saclay) et al., inelastic neutron scattering measurements in the normal state of Sr2RuO4 reveal the existence of incommensurate magnetic spin fluctuations

The cyclotron masses in single-crystal Sr2RuO4 have been measured by S. Hill (Montana State) et al. through the observation of periodic-orbit resonances, a magnetic-resonance technique closely related to cyclotron resonance. The authors obtain values for the alpha, beta, and gamma Fermi surfaces of (4.33+-0.05)m_e, (5.81+-0.03)m_e, and (9.71+-0.11)m_e, respectively. The appreciable differences between these results and those obtained from de Haas-van Alphen measurements are attributable to strong electron-electron interactions in this system. The authors note that their findings are consistent with predictions for a strongly interacting Fermi liquid; semiquantitative agreement is obtained for the electron pockets beta and gamma.

Using a Ginzburg-Landau functional of E_u symmetry due to D. F. Agterberg [Phys. Rev. Lett. 80, 5184 (1998)] and the Landau-level expansion method, T. Kita (Hokkaido) has studied vortex states over the range H_[c1] <= H <= H_[c2] to provide a test of the possibility that p-wave pairing occurs in Sr2RuO4. For the field H in the basal plane, the author finds that (a) a second superconducting transition should be present irrespective of the field direction, (b) below this transition, a characteristic double-peak structure may develop in the magnetic-field distribution, and (c) a third transition may occur between two different vortex states. The author also finds that when the field is along the c axis, the square vortex latter may deform through a second-order transition into a rectangular one as the field is lowered from H_[c2].

Vortices

The dependence of the quasiparticle density of states of a two- dimensional d-wave superconductor upon the orientation of an in-plane external magnetic field H has been calculated by E. Schachinger and J. P. Carbotte (McMaster). The dependence arises because in the region of the gap nodes, the Doppler shift due to the circulating supercurrents around a vortex core depends upon the direction of H. For a tetragonal system, the induced pattern is four-fold symmetric, and the density of states at zero energy exhibits minima when H points along the node directions. In orthorhombic systems, such as YBa2Cu3O6.95, the pattern becomes two-fold symmetric, with the position of the minima occurring when H is oriented along the Fermi velocity at a node on the Fermi surface.

Two different vortex states in a long Josephson junction generated by a nearby Abrikosov vortex are considered in a paper by D. Agassi and J. R. Cullen (NSWC). A conventional state, in which there are no vortices in the junction, has total magnetic flux phi_0 = hc/2e. A second state, which has higher energy, has two antivortices in the junction, such that the total magnetic flux is -phi_0. The energies of the two states tend to the same value as the Abrikosov vortex approaches the Josephson- junction plane.

Using electrical transport measurements, C. Goupil et al. (Caen) have studied the ohmic plastic dissipation of twinned YBCO samples with a magnetic field aligned along the c axis. The authors extracted the activation energy U(T,B) and analyzed it in terms of magnetically induced pinning by twin planes. The presence of twin planes leads to a crossover from a field-independent activation energy at low fields to a B^[-0.5]lnB dependence at high fields. The authors compare this two-step response with similar observations in heavy-ion-irradiated samples.

Using high-resolution SQUID magnetometry, M. Baumann (Hamburg) et al. have studied the influence of columnar defects of field-equivalent density B_[phi] = 1 T on the flux creep in thin YBa2Cu3O7-d films. At temperatures T*(B,B_[phi]), the relaxation rates reveal a sharp crossover from a glassy dynamics to a faster algebraic flux creep, which disappears at the transition lines Tc(B) to equilibrium superconductivity.

The height of the nucleation barrier for vortex penetration into a thin superconducting disk has been calculated by V. A. Schweigert and F. M. Peeters (Antwerpen). The authors made use of an expansion of the order parameter over the eigenfunctions of the linearized first Ginzburg- Landau equation.

A preprint by D. E. Feldman (Texas A&M and Landau Institute) et al. considers the behavior of vortices in a superconducting film on which an array of randomly oriented magnetic dots is placed. The authors find that the concentration of vortices bound to the dots is proportional to the dot density and depends on the dot's magnetization in a step-like way. The concentration of unbound vortices is found to oscillate about a value that is proportional to the magnetic moment of the dots.

Films

The Hall conductivities of HgBa2CaCu2O6+d (Hg-1212) and HgBa2Ca2Cu3O8+d (Hg-1223) thin films in magnetic fields parallel to the c axis have been investigated by W.-S. Kim (POSTECH) et al. The authors report that the mixed-state Hall conductivity is well described by sigma_[xy] = C_1/H + C_2 + C_3H. The prefactor C_1 exhibits a temperature dependence of the form C_1 proportional to (1 - T/Tc)^n near Tc, where the exponent n ~~ 2.3 for Hg-1212 and 1.8 for Hg-1223, comparable with values previously found for YBa2Cu3O7-d and La2-xSrxCuO4. Contrary to previous results, C_2 follows a temperature-scaling behavior similar to that of C_1, but with exponent n' ~~ 3.2 for Hg-1212 and 2.0 for Hg-1223.

In research exploring the possibility of applying metal organic decomposition (MOD) techniques to deposit buffer layers and YBCO films on flexible metallic textured substrates, S. Sathyamurthy and K. Salama (TCSUH) have used the trifluoroacetate (TFA) process to deposit buffer-layer films and YBCO films on single-crystal substrates. YBCO films of thickness 0.3-0.5 micrometers deposited on barium-zirconate-buffered strontium titanate were found to have transition temperatures of 86-88 K and critical current densities of the order of 10^4 A/cm^2 at 77 K in self-field. YBCO films deposited on strontium-titanate-buffered lanthanum aluminate had transition temperatures of 90-91 K and Jcs of the order of 10^5 A/cm^2.

Applications

A preprint by Y. H. Kim (KIST) et al. reports on the design, fabrication, and operation of a single-flux-quantum (SFQ) reset-set (RS) flip-flop based on YBCO grain-boundary junctions on a SrTiO3 bicrystal substrate. The circuit consisted of a read SQUID and an RS flip-flop, which were magnetically coupled. The circuit operated correctly in the temperature range 65-71 K. At 71 K, the circuit operated over 100 RS operations without error. The authors also measured the effect of noise on switching a Josephson junction to the voltage state in an SFQ circuit.

The nonlinear surface impedance of a thin superconducting strip carrying a microwave current has been calculated numerically by T. Dasgupta et al. (Northeastern). The calculations, based upon flux penetration due to a current-induced critical state, approach known analytic results in the thin-film limit. The authors suggest that their numerical technique will be useful in the design of passive superconducting microwave

Using two lock-in amplifiers and an appropriate correction scheme, S. Krueger-Olsen (TU Denmark) et al. have measured the ac losses of a low-loss 10 m long Bi-2223/Ag superconducting cable. The 1 microvolt/cm critical current of the conductor was 3240 A at 77 K, and at an rms current of 2 kA, the 50 Hz ac loss was found to be (0.6+-0.15) W/m. The authors believe this to be the lowest ac power loss of a high- temperature superconducting cable reported so far at such high currents.

Theory

A theory of angle-resolved photoemission (ARPES) in doped cuprates and other charge-transfer Mott insulators has been developed by A. S. Alexandrov and C. J. Dent (Loughborough), taking into account a realistic (LDA+U) band structure, (bi)polaron formation due to the strong electron-phonon interaction, and a random field potential. In most of these materials, the first band to be doped is the oxygen band inside the Mott-Hubbard gap. The authors derive the coherent part of the ARPES spectra with the oxygen hole spectral function calculated in the noncrossing (ladder) approximation and with the exact spectral function of a one-dimensional hole in a random potential. Some unusual features of ARPES, including the polarization dependence and spectral shape in YBa2Cu3O7 and YBa2Cu4O8, are described without any Fermi surface, large or small. The authors assert that the theory is compatible with the doping dependence of kinetic and thermodynamic properties of the cuprates, as well as with the d-wave symmetry of the superconducting order parameter.

The ground state of the two-dimensional Hubbard model has been studied by Y. Asai (ETL) using a quantum Monte Carlo method and paying special attention to the shell-structure effect on finite-size clusters (6 x 6 and 10 x 10 lattices). The calculations show that there is a gap for spin excitations in the ground state and incommensurate peaks at (pi+-d,pi) and (pi,pi+-d) in the spin correlation function for a low-lying excited state. In the ground state, the long-range part of the d-wave superconducting correlation function is enhanced, and the momentum distribution function at the Fermi level (pi,0) is rounded. The gap in spin excitations and the momentum distribution function rounding is consistent with the opening of a d-wave superconducting gap in the ground state.

According to a preprint by V. M. Loktev (Kiev) et al., the presence of nonmagnetic impurities in a 2D "bad metal" depresses the superconducting Berezinskii-Kosterlitz-Thouless transition temperature, while leaving the pairing scale unchanged. Thus, in the presence of nonmagnetic impurities, the pseudogap phase, where the modulus of the order parameter is nonzero but its phase is random, is bigger than it is for the clean system. In addition, the theoretical temperature dependence of the superfluid density in the presence of impurities is closer to experiment than that in the clean limit.

Using a large-N expansion, A. Greco (Rosario) and R. Zeyher (MPI-Stuttgart) solve the linearized equation for the superconducting gap for a generalized t-J model that also contains phonons within a Holstein model. Keeping all terms up to O(1/N), the authors find that the kernel of the gap equation consists of an electron-phonon part with self- energies and vertex functions renormalized by the interactions of the t-J model, and a t-J part unaffected by phonons. Including both the electron-phonon part and the t-J part in the gap equation, the authors find that the leading Tc always has d-wave symmetry, with phonons giving a positive contribution to Tc.

The effect of the Zeeman magnetic field in the superconducting phase in a two-component order-parameter scenario, such as d_[x^2-y^2] + e^[i*theta]alpha, where alpha = d_[xy] or s, has been studied by H. Ghosh (Arizona). The author notes that this scenario is equivalent to applying a magnetic field parallel to the CuO2 planes.

Current fluctuations in a normal-metal/d-wave superconductor junction with a [110]-oriented interface have been investigated by J. X. Zhu and C. S. Ting (TCSUH). The authors find that the sign change of the d-wave order parameter has an important effect on the voltage dependence of the shot-noise power. The predicted current-fluctuation behavior is qualitatively different from that in a normal-metal/s-wave superconductor junction.

A three-dimensional lattice of Josephson junctions with a finite self-inductance has been used by M. S. Li (Warsaw) to model ceramic superconductors. The author studied the nonlinear ac susceptibility, second-harmonic generation in the presence of a dc magnetic field, and the compensation effect discussed by Ch. Heinzel et al. [Phys. Rev. B 48, 3445 (1993)] in studies of the paramagnetic Meissner effect (PME). Using Monte Carlo simulations modeling an array of 0- and pi-junctions, the author finds, in agreement with experiment, that the compensation effect may be present in ceramic superconductors that show the PME.

A numerical technique for recovering the missing phase information for a set of critical current measurements as a function of the applied magnetic field I_c(B) is described by M. Carmody (Argonne and Northwestern) et al. The authors assert that in many cases the profile of the maximum Josephson critical current density J_0(x) along the length of the boundary can be determined.

As noted in a preprint by V. A. Schweigert and F. M. Peeters (Antwerpen), the nucleation field for surface superconductivity, H_[c3], depends on the geometrical shape of the sample and is substantially enhanced with decreasing sample size. The authors studied circular, square, triangular, and wedge-shaped disks of uniform thickness in a perpendicular magnetic field. For a wedge with interior angle alpha, the authors found that the nucleation field diverges as H_[c3]/H_[c2] = 3^[1/2]/alpha in the limiting case of alpha << 1. For alpha = pi/2, the authors found H_[c3]/H_[c2] = 1.96, and for alpha = pi, they recovered the well-known result H_[c3]/H_[c2] = 1.695.

Other Activities

To test for the possibility of a gravity shielding effect in the superconducting state, H. Reiss (ABB, Heidelberg) measured the weight of a pile of Bi-2212 pellets inside a sample holder submerged in liquid nitrogen as the sample cooled to 77 K. The apparent weight increased with time (as the sample cooled) when the sample holder contained superconductors, normal conductors, or nonconductors. This was a consequence of the continuously reduced convective liquid motion and bubble lift-off. The author reports that the superconductor samples, however, gained slightly more weight than the normal or nonconductors, giving rise to a relative increase of the superconductor sample weights by about 0.5%, which the author tentatively interprets as a gravity shielding effect. Application of an external magnetic field, produced by permanent magnets placed on the top and bottom of the stack of superconducting pellets inside the sample holder, eliminated the observed effect. The author welcomes comments from colleagues who would be able to confirm or reject the observations.

A preprint by P. Kumar (Florida) et al. suggests that the transition to superconductivity in a single crystal of Ba0.6K0.4BiO3 (Tc = 32 K), having critical fields with anomalous temperature dependencies and vanishing discontinuities in the specific heat and magnetic susceptibility, may be an example of a fourth-order (in Ehrenfest's sense) phase transition. The authors have derived a free-energy functional for a fourth-order transition and calculated (for the temperature range Tc/2 < T <= Tc) the temperature dependence of the critical fields. The authors find that H_[c1](T) proportional to (1 - T/Tc)^3, H_c(T) proportional to (1 -T/Tc)^2, and H_[c2](T) proportional to (1 - T/Tc)^1, in general agreement with experiments.

A systematic study of the time evolution of the transport critical current in polycrystalline samples of the high-temperature superconductors (Hg1-xRex)Ba2Ca2Cu3O8+d [(Hg,Re)-1223] and YBa2Cu3O7-d (Y-123) after application and removal of an external magnetic field has been carried out by E. Altshuler (Havana) et al. The transport critical current was found to increase logarithmically with time. The authors explain this finding in terms of a model in which the transport critical current is determined by the effective field in the intergrain junctions, which relaxes logarithmically with time because of intragranular flux creep.

The peak effect in the critical current in CuBa2SmCu2O7-d (Cu-1212:P or Sm-123), CuBa2Ca3Cu4O10+d (Cu-1234), (Hg,Pb)(Ba,Sr)2Ca2Cu3O8+d [(Hg,Pb)-1223], and YBCO melt-grown composites has been studied by H. Yamauchiet al. (Tokyo Tech). The authors conclude that the peak effect in various layered copper-oxide superconductors is most likely caused by rather periodic modulations of the local superconducting properties with aperiod of tens of nanometers.

Experimental data obtained by different techniques are examined by A. Mourachkine (Brussels). The author finds that the data are not easy to explain by any theoretical model presented in the literature, but can be explained by an MCS model (magnetic coupling of stripes).

Overviews

An overview by J. B. Marston (Brown) argues that recent years have seen a consilience, a coming together, of theories of high-temperature superconductivity. The author stresses that some of the more promising descriptions - gauge theories, coupled chains, nesting instabilities, nodal liquids, and stripes - share features in common (57 refs.).

Contributed by John R. Clem

Contents: Technology News is on page 6; Preprints begin on page 7; and Coming Events are on page 11.

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.

TECHNOLOGY NEWS (Also see Applications section of Nota Bene.)

This section describes progress in manufacturing, product development, and technology transfer in the high-Tc superconductivity field. Please send your contributions (product development information, news regarding technology transfer efforts, or any information you would like to share about your corporation or laboratory) to the editor.

Recently, American Superconductor Corporation announced its first order to install a Distributed Superconducting Magnetic Energy Storage (D-SMES) system to improve reliability and capacity in an electric-utility network. The D-SMES system will consist of six individual SMES units that will be deployed within the next year at five electrical substations in a large-scale transmission network in the Wisconsin Public Service Corporation service territory. This order launches a new product line for the SMES technology and company officials anticipate the D-SMES system will play a key role in improving power transmission reliability while increasing the effective operating capacity of existing power transmission networks. Wisconsin Public Service (WPS) will deploy the D-SMES system in its Northern Transmission Loop, a network approximately 200 miles in circumference that is located in the Wausau and Eagle River areas of Wisconsin. Network analyses, performed by American Superconductor with WPS, identified precise locations for the SMES units within the network for optimum voltage stabilization in the event of transients in the system caused by such factors as severe weather, traffic accidents, or unanticipated equipment failures. Installation of the units is planned to begin in January and be completed and online by March 2000. For this first D-SMES system, American Superconductor included an innovative buyback provision that gives Wisconsin Public Service a high degree of flexibility in strengthening its position in the new, competitive utility environment. For further information, contact American Superconductor Corporation, Two Technology Drive, Westborough, MA 01581; telephone (508) 836-4200; telefax (508) 836-4248. Media contact is Kevin Coates, telephone (202) 434-8308, e-mail kcoates@washington.com.

At the AEA Financial Growth Summit in Monterey, Calif., Conductus, Inc. announced an agreement with General Dynamics to jointly develop HTS technology and pursue government market opportunities. Under this agreement General Dynamics Information Systems (GDIS) will purchase rights to Conductus' HTS thin-film technology and other intellectual property for $5M plus future royalties, and will have exclusive rights to use and sell this technology in the government marketplace. Conductus will continue to develop, design, and manufacture products for GDIS as part of a separate Cross-License, Supply and Training agreement. For information, contact Conductus, Inc. 969 W. Maude Avenue, Sunnyvale, CA 94086; telephone (408) 523-9950; telefax (408) 523-9999.

Contributed by Sreeparna Mitra

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.

D. Agassi and J. R. Cullen, "New Vortex State in the Presence of a Long Josephson Junction." To be published in Physica C (in press). Code 68, Carderock Division, Naval Surface Warfare Center, 9500 MacArthur Blvd., West Bethesda, MD 20817; telefax (301) 227-4733; e-mail agassi@oasys.dt.navy.mil. Key words: Josephson junction, vortex state, Abrikosov vortex.

Ian J.R. Aitchison, Dominic J. Lee, and Georgios Metikas, "Finite Temperature Time-Dependent Effective Theory for the Goldstone Field in a BCS Superconductor." Preprint #OUTP-98-82P; to be published in Phys. Rev. B. Department of Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP, UNITED KINGDOM; e-mail i.aitchison1@physics.oxford.ac.uk; Georgios Metikas' telephone +44 1865-273950 or -273999; e-mail g.metikas1@physics.oxford.ac.uk; preprint also available at http://xxx.lanl.gov/abs/cond-mat/9905008.

A. S. Alexandrov and C. J. Dent, "Angle-Resolved Photoemission in Doped Charge-Transfer Mott Insulators." Submitted to Phys. Rev. B. Department of Physics, Loughborough University, Loughborough Leicestershire LE11 3TU, UNITED KINGDOM; telephone +44 1509 223303; telefax +44 1509 223986; e-mail asa21@cus.cam.ac.uk. 74.20.Mn; 74.20.-z; 74.25.Jb.

E. Altshuler, R. Cobas, A. J. Batista-Leyva, C. Noda, L. E. Flores, C. Martinez, and M.T.D. Orlando, "Relaxation of the Transport Critical Current in HTc Polycrystals." To be published in Phys. Rev. B. Superconductivity Laboratory, IMRE-Physics Faculty, University of Havana, 10400 Havana, CUBA.

Yoichi Ando, A. N. Lavrov, and Kouji Segawa, "Magnetoresistance Anomalies in Antiferromagnetic YBa2Cu3O6+x: Fingerprints of Charged Stripes." Submitted to Phys. Rev. Lett. Central Research Institute of Electric Power Industry (CRIEPI), 2-11-1 Iwato-kita, Komae, Tokyo 201-8511, JAPAN; A. N. Lavrov's telephone +81 3 3480 2111; telefax +81 3 3480 3401; e-mail lavrov@criepi.denken.or.jp; preprint also available at http://xxx.lanl.gov/abs/cond-mat/9905071. 74.25.Fy; 74.20.Mn; 74.72.Bk.

Yoshihiro Asai, "The Ground and Low Lying Excited States of the Two-Dimensional Hubbard Model." Physical Science Division, Electrotechnical Laboratory (ETL), Agency of Industrial Science and Technology (AIST), Umezono 1-1-4, Tsukuba, Ibaraki 305, JAPAN; e-mail yoasai@etl.go.jp; preprint also available at http://xxx.lanl.gov/abs/cond-mat/9904310. 71.10.Fd; 74.20.Mn; 75.40.Mg.

M. Baumann, G. Wirth, and J. Koetzler, "Vortex Dynamics in Columnar-Defected YBCO-Films." Submitted to Physica A (in press). Institut fuer Angewandte Physik und Zentrum fuer Mikrostrukturforschung, Universitaet Hamburg, Jungiusstr. 11, D-20355 Hamburg, GERMANY.

C. Benvenuti, S. Calatroni, I. E. Campisi, P. Darriulat, M. A. Peck, R. Russo, and A.-M. Valente, "Study of the Surface Resistance of Superconducting Niobium Films at 1.5 GHz." To be published in Physica C (in press). Contact P. Darriulat, CERN, CH-1211 Geneve 23, SWITZERLAND; telephone +41 22 767 3397; telefax +41 22 767 9150; e-mail darriulat@cern.ch. Key words: microwave absorption, flux pinning, BCS model, niobium films.

E. V. Blinov, R. Laiho, A. G. Lyublinsky, E. Laehderanta, and K. B. Traito, "Reentrant Reversible Remanent Magnetization in Superconducting Submicron YBaCuO Particles." To be published in Physica C (in press). Contact E. Laehderanta, Wihuri Physical Laboratory, University of Turku, FIN-20014 Turku, FINLAND; telephone +358 2 333 5650; telefax +358 2 231 9836; e-mail erkki.lahderanta@utu.fi. Key words: London penetration depth, magnetization, mixed state. 74.25.Ha; 74.20.De; 74.80. Bj.

M. Carmody, E. Landree, L. D. Marks, and K. L. Merkle, "Determination of the Current Density Distribution in Josephson Junctions." To be published in Physica C (in press). Materials Science Division and Science and Technology Center for Superconductivity, Bldg. 212, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439; telephone (630) 252-5181; e-mail carmody@anl.gov. Key words: Josephson junctions, phase retrieval, critical current density. 74.25.Fy; 74.25.Ha; 73.40.Gk.

T. Dasgupta, Durga P. Choudhury, and S. Sridhar, "Modeling Nonlinearity and Hysteresis Due to Critical-State Flux Penetration in Hard Superconductors." Submitted to IEEE Trans. Appl. Supercond. Department of Physics, Northeastern University, 360 Huntington Avenue, Boston, MA 02115; P. Choudhury's e-mail dpc@neu.edu; preprint also available at http://xxx.lanl.gov/abs/cond-mat/9905063 or http://sagar.physics.neu.edu/. Key words: critical state, hysteresis, nonlinearity, microwave transmission lines.

J. Demsar, B. Podobnik, V. V. Kabanov, D. Mihailovic, and Th. Wolf, "The Superconducting Gap Delta_c, the Pseudogap Delta_p and Pair Fluctuations Above Tc in Overdoped Y1-xCaxBa2Cu3O7-d from Femtosecond Time-Domain Spectroscopy." To be published in Phys. Rev. Lett. Solid State Physics Department, Jozef Stefan Institute, Jamova 39, 1001 Ljubljana, SLOVENIA; e-mail jure.demsar@ijs.si; preprint also available at http://xxx.lanl.gov/abs/cond-mat/9905026.

D. E. Feldman, I. F. Lyuksyutov, and V. L. Pokrovsky, "Vortex Plasma in a Superconducting Film with Magnetic Dots." Department of Physics, Texas A&M University, College Station, TX 77843-4242; e-mail dima@rainbow.physics.tamu.edu; preprint also available at http://xxx.lanl.gov/abs/cond-mat/9905025.

Shigeki Fujiyama, Masashi Takigawa, Yutaka Ueda, Tomoyuki Suzuki, and Nobuyoshi Yamada, "Nuclear Spin-Spin Coupling in La2-xSrxCuO4 Studied by Stimulated Echo Decay." Technical Report of ISSP, Ser. A #3475. Institute for Solid State Physics, The University of Tokyo, 7-22-1 Roppongi, Minato-ku, Tokyo 106-8666, JAPAN; e-mail fujiyama@kodama.issp.u-tokyo.ac.jp; preprint also available at http://xxx.lanl.gov/abs/cond-mat/9904275.

Ryogi Funahashi, Ichiro Matsubara, Kazuo Ueno, and Katsunori Mizuno, "Isotropic Pinning in Heavily Pb-Doped Bi-2212/Ag Tapes." To be published in Physica C (in press). Osaka National Research Institute, AIST, Midorigaoka, Ikeda, Osaka 563-8577, JAPAN; telephone +81 727 51 9541; telefax +81 727 51 9622; e-mail fune@onri.go.jp. Key words: Bi2Sr2CaCu2Ox/Ag tapes, heavy Pb doping, isotropic pinning, isotropic transport Jc.

Haranath Ghosh, "Superconductors of Mixed Order Parameter Symmetry in a Zeeman Magnetic Field." To be published in Phys. Rev. B. Department of Physics, University of Arizona, Tucson, AZ 85721; e-mail hng@physics.arizona.edu; preprint also available at http://xxx.lanl.gov/abs/cond-mat/9904375. 74.25.Nf; 74.25.Dw; 74.62.-c.

Gregory N. Gol'tsman and Eugene M. Gershenzon, "Phonon-Cooled Hot-Electron Bolometric Mixers: Overview of Recent Results." To be published in Appl. Supercond. (in press). Department of Physics, Moscow State Pedagogical University, 119435 Moscow, RUSSIA.

C. Goupil, F. Warmont, M. Hervieu, J. F. Hamet, and Ch. Simon, "Magnetoresistance and Plastic Dissipation in Twinned YBaCuO Samples." To be published in Phys. Rev. B. Laboratoire CRISMAT, ISMRA, 6 Boulevard du Marechal Juin, F-14050 Caen Cedex, FRANCE; telephone +33 2 31 45 2686; e-mail ch.goupil@crismat.ismra.fr.

A. Greco and R. Zeyher, "Electronic Correlations, Electron-Phonon Interaction, and Isotope Effect in High-Tc Cuprates." To be published in Phys. Rev. B. Departamento de Fisica, Facultad de Ciencias Exactas e Ingenieria and IFIR(UNR-CONICET), Av. Pellegrini 250, 2000 Rosario, ARGENTINA; R. Zeyher's e-mail zeyher@greta5.mpi-stuttgart.mpg.de; preprint also available at http://xxx.lanl.gov/abs/cond-mat/9904374. 74.20.Mn; 74.25.Kc; 74.20.-z.

M. Grueninger, D. van der Marel, A. Damascelli, A. Erb, Th. Wolf, T. Nunner, and T. Kopp, "Mid-Infrared Absorption in YBa2Cu3O6: Failure of Spin-Wave Theory in Undoped Cuprates?" Solid State Physics Laboratory, University of Groningen, Nijenborgh 4, 9747 AG Groningen, THE NETHERLANDS; telephone +31 50 363 4812; telefax +31 50 363 4825; e-mail markus@phys.rug.nl; preprint also available at http://xxx.lanl.gov/abs/cond-mat/9904394. 74.72.-h; 74.25.Gz; 78.30.Hv; 75.40.Gb; 75.50.Ee.

Tero T. Heikkilae, Martti M. Salomaa, and Colin J. Lambert, "The Superconducting Proximity Effect and Universal Conductance Fluctuations." Materials Physics Laboratory, Helsinki University of Technology, P.O. Box 2200, FIN-02015 HUT, FINLAND; e-mail ttheikki@focus.hut.fi; preprint also available at http://xxx.lanl.gov/abs/cond-mat/9904016.

S. Hill, J. S. Brooks, Z. Q. Mao, and Y. Maeno, "Cyclotron Resonance in the Layered Perovskite Superconductor Sr2RuO4." Department of Physics, Montana State University, Bozeman, MT 59717; telephone (406) 994-7175; telefax (406) 994-4452; e-mail hill@physics.montana.edu; preprint also available at http://xxx.lanl.gov/abs/cond-mat/9905147. 71.18.+y; 71.27.+a; 74.25.Nf.

Wan-Seon Kim, W. N. Kang, S. J. Oh, Mun-Seog Kim, Yujoung Bai, Sung-Ik Lee, Chang Ho Choi, and H.-C. Ri, "Temperature-Scaling Behavior of the Hall Conductivity for Hg-Based Superconducting Thin Films." Submitted to Phys. Rev. B. National Creative Research Initiative Center for Superconductivity and Department of Physics, Pohang University of Science and Technology, Pohang 790-784, SOUTH KOREA; W. N. Kang's e-mail wnkang@postech.ac.kr; preprint also available at http://xxx.lanl.gov/abs/cond-mat/9904385. 74.60.Ge; 74.25.Fy; 74.72.Gr; 74.76.-w.

Y. H. Kim, J. H. Kang, J. M. Lee, T. S. Hahn, S. S. Choi, J. H. Park, D. H. Kim, and S. J. Park, "HTS SFQ Logic Circuit Built with YBCO Grain Boundary Junctions." To be published in Appl. Supercond. (in press). Superconductivity Research Laboratory, Korea Institute of Science and Technology, P.O. Box 131, Cheongryang, Seoul 130-650, KOREA.

Takafumi Kita, "Vortex States of the E_u Model for Sr2RuO4." Division of Physics, Hokkaido University, Sapporo 060-0810, JAPAN; e-mail kita@phys.sci.hokudai.ac.jp; preprint also available at http://xxx.lanl.gov/abs/cond-mat/9905068.

M. Kiuchi, A. Yamasaki, T. Matsushita, J. Fujikami, and K. Ohmatsu, "Distribution of Flux Pinning Strength in a Superconducting Bi-2223 Silver-Sheathed Tape." To be published in Physica C (in press). Graduate School of Information Science and Electrical Engineering (ISEE), Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, JAPAN; telephone +81 92 642 3893; telefax +81 92 642 3963; e-mail kiuchi@ees.kyushu-u.ac.jp. Key words: flux pinning strength, Bi-2223 silver-sheathed tape, Weibull function.

Erik Koch, Olle Gunnarsson, and Richard M. Martin, "Screening of a Point Charge: A Fixed-Node Diffusion Monte Carlo Study." To be published in Proc. of the Workshop on Recent Developments in Computer Simulation Studies in Cond. Mat. Phys., edited by D. P. Landau et al. (Springer Verlag, Berlin, 1999). Max-Planck-Institut fuer Festkoerperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, GERMANY; e-mail koch@anpow2.mpi-stuttgart.mpg.de; preprint also available at http://xxx.lanl.gov/abs/cond-mat/9904257.

Erik Koch, Olle Gunnarsson, and Richard M. Martin, "Screening, Coulomb Pseudopotential, and Superconductivity in Alkali-Doped Fullerenes." Max-Planck-Institut fuer Festkoerperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, GERMANY; e-mail koch@anpow2.mpi-stuttgart.mpg.de; preprint also available at http://xxx.lanl.gov/abs/cond-mat/9902241. 74.70.Wz; 71.10.Fd; 71.20.Tx.

P. Kumar, Donavan Hall, and R. G. Goodrich, "Thermodynamics of the Superconducting Phase Transition in Ba0.6K0.4BiO3." To be published in Phys. Rev. Lett. Department of Physics, University of Florida, Gainesville, FL 32611; Donavan Hall's e-mail at Florida State University hall@magnet.fsu.edu; preprint also available at http://xxx.lanl.gov/abs/cond-mat/9904288.

J. Kurian, S. P. Pai, P. K. Sajith, K.V.O. Nair, K. S. Kumar, and J. Koshy, "Development and Characterization of Dysprosium Barium Niobate: A New Substrate for YBa2Cu3O7-d and (Bi,Pb)2Sr2Ca2Cu3Ox Superconductor Films." To be published in Physica C (in press). Contact J. Koshy, Electronic Ceramics, Regional Research Laboratory (CSIR), Trivandrum, Kerala 695 019, INDIA; telephone +91 471 49 0674; telefax +91 471 49 0186; e-mail jacob@csrrltrd.ren.nic.in. Key words: dysprosium barium niobate, YBa2Cu3O7-d, (Bi,Pb)2Sr2Ca2Cu3Ox.

K. Kwasnitza, S. Clerc, R. Fluekiger, and Y. Huang, "Reduction of Alternating Magnetic Field Losses in High-Tc Multifilament Bi(2223)/Ag Tapes by High Resistive Barriers." Submitted to Cryogenics. Paul Scherrer Institut, CH-5232 Villigen PSI, SWITZERLAND; telephone +41 56 310-3593 or -2111; telefax +41 56 310-3131. Key words: high-Tc superconductors, 50 Hz ac losses, ceramic barriers.

Mai Suan Li, "Second Harmonics and Compensation Effect in Ceramic Superconductors." To be published in Phys. Rev. B. Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, PL 02-668 Warsaw, POLAND; preprint also available at http://xxx.lanl.gov/abs/cond-mat/9904401. 75.40.Gb; 74.72.-h.

Vadim M. Loktev, Rachel M. Quick, and Sergei G. Sharapov, "Phase Fluctuations and Pseudogap Properties: Influence of Nonmagnetic Impurities." Bogolyubov Institute for Theoretical Physics, 252143 Kiev, UKRAINE; e-mail vloktev@bitp.kiev.ua; preprint also available at http://xxx.lanl.gov/abs/cond-mat/9904126. 74.40.+k; 74.62.Dh; 74.72.-h.

S. Marinel, D. Bourgault, O. Belmont, A. Sotelo, and G. Desgardin, "Microstructure and Transport Properties of YBCO Zone Melted Samples Processed in a Microwave Cavity and Infrared Furnace." To be published in Physica C (in press). Laboratoire CRISMAT, CNRS UMR 6508, ISMRA et Universite de Caen, 6 Boulevard du Marechal Juin, F-14050 Caen Cedex, FRANCE; e-mail marinel@crismat.ismra.fr. Key words: critical current density, grain alignment, grain boundaries.

J. B. Marston, "Consilience of High-Tc Theories." Submitted to the Proc. of the Int. Workshop on Superconductivity, Magnetoresistive Materials and Strongly Correlated Systems, Vietnam. Department of Physics, Brown University, Providence, RI 02912-1843; telephone (401) 863-2061; e-mail marston@physics.brown.edu or jbm@barus.physics.brown.edu; preprint also available at http://xxx.lanl.gov/abs/cond-mat/9904437.

T. Motohashi, Y. Nakayama, T. Fujita, K. Kitazawa, J. Shimoyama, and K. Kishio, "Systematic Decrease of Resistivity Anisotropy in Bi2Sr2CaCu2Oy by Pb Doping." To be published in Phys. Rev. B. Department of Superconductivity, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-8656, JAPAN; telephone +81 3 3812 2111, ext. 7711; telefax +81 3 5689 0574; e-mail tt67217@hongo.ecc.u-tokyo.ac.jp. 74.25.Fy; 74.62.Dh; 74.72.Hs.

A. Mourachkine, "The MCS Model of the Superconductivity in Hole-Doped Cuprates: An Experimental Evidence." Submitted to J. Supercond. Service de Physique des Solides, Universite Libre de Bruxelles, CP233, Boulevard du Triomphe, B-1050 Brussels, BELGIUM; telephone +32 2 650 5751; telefax +32 2 650 5916; e-mail anmourac@ulb.ac.be; preprint also available at http://xxx.lanl.gov/abs/cond-mat/9904445.

Y. Nakamura, K. Tachibana, and H. Fujimoto, "The Size and Morphology of Silver in the YBa2Cu3O6+x Crystal." To be published in Physica C (in press). Railway Technical Research Institute, 2-8-38 Hikari-cho, Kokubunji, Tokyo 185-8540, JAPAN; telephone +81 42 573 7297; telefax +81 42 573 7360; e-mail yuichi_n@rtri.or.jp. Key words: silver, Y123, morphology.

Y. Nakayama, N. Takase, M. Kiuchi, T. Matsushita, and T. Hasegawa, "Effect of Distribution of Flux Pinning Strength on Irreversibility Line

and Vortex Glass-Liquid Transition Line in a Bi-2212 Tape Wire." To be published in Physica C (in press). Contact T. Matsushita, Department of Computer Science and Systems Engineering, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka 820-8502, JAPAN; telephone +81 948 29 7663; telefax +81 948 29 7683; e-mail matusita@cse.kyutech.ac.jp. Key words: glass, liquid, Bi-2212.

T. Niemoeller, H. Huennefeld, J. R. Schneider, N. Ichikawa, S. Uchida, T. Frello, N. H. Andersen, and J. M. Tranquada, "Charge Stripes Seen with X-rays in La1.45Nd0.4Sr0.15CuO4." Hamburger Synchrotronstrahlungslabor HASYLAB, Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, D-22603 Hamburg, GERMANY; e-mail niemoell@hasyhep3.desy.de; preprint also available at http://xxx.lanl.gov/abs/cond-mat/9904383. 61.10.Nz; 74.72.Dn.

S. Krueger Olsen, A. Kuehle, C. Traeholt, C. Rasmussen, T. Tonnesen, M. Daeumling, C. N. Rasmussen, and D.W.A. Willen, "ac Losses of a 10 Meter Long Low Loss Superconducting Cable Conductor Determined from Phase Sensitive Measurements." To be published in Supercond. Sci. & Technol. Department of Electric Power Engineering, Bldg. 325, Technical University of Denmark, DK-2800 Lyngby, DENMARK; telephone +45 45 88-3517 or -1633; telefax +45 45 88-6111; e-mail sko@eltek.dtu.dk. 74.60.Jg; 85.25.Kx; 84.70.+p.

K. S. Ramesh and M. S. Ramachandra Rao, "Effect of Grain Network Modifications Due to Additives on Critical Current (I_c) in Bi-2212 Superconductor." To be published in Physica C (in press). Contact M. S. Ramachandra Rao, Materials Science Research Centre and Department of Physics, Indian Institute of Technology, Madras, Chennai 600 036, INDIA; e-mail msrc@iitm.ernet.in. Key words: critical current, weak links, additives, proximity effect. 74.72.Hs; 74.25.Fy; 74.50.+r.

Harald Reiss, "A Possible Interaction Between Gravity and High Temperature Superconductivity--By a Materials Property?" Submitted to the 15th. European Conf. Thermophys. Properties, Wuerzburg, Germany, Sept. 5-9, 1999. Asea Brown Boveri Forschungszentrum, Postfach 10 13 32, Speyerer Strasse 4, D-69115 Heidelberg, GERMANY; telephone +49 6221 59 6459; telefax +49 6221 59 6163; e-mail harald.reiss@decrc.mail.abb.com. Key words: high-temperature superconductivity, BiSrCaCuO (2212) pellets, magnetic field, Meissner state, gravity.

Richard D. Saam, "Superconductivity, the Structure Scale of the Universe (Second Edition)." Technical Report 0401993. Proteus Systems, Inc., 525 Louisiana Ave., Corpus Christi, TX 78404; telephone (361) 855-1265; telefax (361) 888-5834; e-mail rdsaam@worldnet.att.net; preprint also available at http://xxx.lanl.gov/abs/cond-mat/9905007. S. Sathyamurthy and K. Salama, "Application of Metal Organic Decomposition Techniques for the Deposition of Buffer Layers and Y123 for Coated-Conductor Fabrication." Preprint #99:030; submitted to Physica C. Texas Center for Superconductivity, University of Houston, Houston, TX 77204-5932; telephone (713) 743-8200; telefax (713) 743-8201; e-mail preprints@www.tcs.uh.edu.

E. Schachinger and J. P. Carbotte, "Magnetic Field Effects on the Density of States of Orthorhombic Superconductors." Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, CANADA L8S 4M1; e-mail schachinger@itp.tu-graz.ac.at; preprint also available at http://xxx.lanl.gov/abs/cond-mat/9904305. 74.20.Fg; 74.25.Ha; 74.72.-h.

V. A. Schweigert and F. M. Peeters, "Flux Penetration and Expulsion in Thin Superconducting Disks." Departement Natuurkunde, Universiteit Antwerpen (UIA), Universiteitsplein 1, B-2610 Antwerpen, BELGIUM; F. M. Peeter's e-mail peeters@uia.ua.ac.be. 74.25.Ha; 74.60.Ec; 73.20.Dx. V. A. Schweigert and F. M. Peeters, "Influence of the Confinement Geometry on Surface Superconductivity." To be published in Phys. Rev. B. Departement Natuurkunde, Universiteit Antwerpen (UIA), Universiteitsplein 1, B-2610 Antwerpen, BELGIUM; F. M. Peeter's e-mail peeters@uia.ua.ac.be; preprint also available at http://xxx.lanl.gov/abs/cond-mat/9905016. 74.80.-g; 74.20.De.

Y. Sidis, M. Braden, P. Bourges, B. Hennion, S. Nishizaki, Y. Maeno, and Y. Mori, "Evidence for Incommensurate Spin Fluctuations in Sr2RuO4." Laboratoire Leon Brillouin, CEA-CNRS, CE Saclay, F-91191 Gif sur Yvette, FRANCE; P. Bourges' e-mail bourges@bali.saclay.cea.fr; preprint also available at http://xxx.lanl.gov/abs/cond-mat/9904348.

Augusto Smerzi and Srikanth Raghavan, "Macroscopic Quantum Fluctuations in the Josephson Dynamics of Two Weakly Linked Bose-Einstein Condensates." Contact Srikanth Raghavan, Rochester Theory Center for Optical Science and Engineering and Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627; telephone (716) 275-8533; telefax (716) 275-8527; e-mail srirag@pas.rochester.edu; preprint also available at http://xxx.lanl.gov/abs/cond-mat/9905059. 74.50.+r; 03.75.Fi.

A. Sobha, R. P. Aloysius, P. Guruswamy, K.G.K. Warrier, and U. Syamaprasad, "Effects of Ag, Ag2O and AgNO3 Additions in (Bi,Pb)-2223/Ag Powder-in-Tube Tapes." To be published in Physica C (in press). Contact U. Syamaprasad, Regional Research Laboratory (CSIR), Trivandrum 695 019, INDIA; telefax +91 471-491712 or -490186; e-mail smail@csrrltrd.ren.nic.in. Key words: (Bi,Pb)-2223/Ag tapes, Ag additives, critical current density.

Hideyoshi Tanabe, Isao Tanaka, Satoshi Watauchi, and Hironao Kojima, "Growth of La2-xSrxCuO4 Single-Crystalline Films by Liquid Phase Epitaxial Technique." To be published in Physica C (in press). Contact Isao Tanaka, Institute of Inorganic Synthesis, Faculty of Engineering, Yamanashi University, Miyamae 7, Kofu, Yamanashi 400-8511, JAPAN; telephone +81 55 220 8625; telefax +81 55 254 3035; e-mail itanaka@mail.yamanashi.ac.jp. Key words: liquid-phase epitaxy, magnetization, thin films, single-crystal growth, substitution effects, cuprate superconductor. 68.55.-a; 74.76.Bz; 81.10.Dn.

R. P. Vasquez, M. P. Siegal, D. L. Overmyer, Z. F. Ren, J. Y. Lao, and J. H. Wang, "Chemical Bonding in Tl Cuprates Studied by X-ray Photoemission." To be published in Phys. Rev. B (in press). Center for Space Microelectronics Technology, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109-8099; e-mail richard.vasquez@jpl.nasa.gov. 74.72.Fq; 79.60.-i; 74.76.Bz; 74.62.Bf.

Z. J. Wu, Q. B. Meng, and S. Y. Zhang, "Valences of Cu and Tl and Chemical Bond Parameters in TlxBa2CuyO6+d, Tl2Ba2CaCu2O8, and Tl2Ba2Ca2Cu3O10." To be published in Physica C (in press). Laboratory of Rare Earth Chemistry and Physics, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, P.O. Box 1022, Changchun 130022, PEOPLE'S REPUBLIC OF CHINA; telefax +86 431 568 5653; e-mail zjwu@ns.ciac.jl.cn. Key words: valence, chemical bond, Tl/Cu ratio.

H. Yamauchi, T. Akao, and H. Suematsu, "The Peak Effect in High Tc Superconductors." To be published in the Proc. of the 2nd Int. Symp. on Electronic Component Mater., KAIST, Daejon, Korea, May 7, 1999. Materials & Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 227, JAPAN; telephone +81 45 924-5315; telefax +81 45 924-5365 or -5360; e-mail yamauchi@materia.titech.ac.jp.

J. X. Zhu and C. S. Ting, "Shot Noise in a Normal Metal-d-Wave Superconductor Junction with a {110}-Oriented Interface." Preprint #99:038; to be published in Phys. Rev. B. Department of Physics and Texas Center for Superconductivity, University of Houston, Houston, TX 77204-5932; telephone (713) 743-8200; telefax (713) 743-8201; e-mail preprints@www.tcs.uh.edu. 74.80.Fp; 74.50.+r; 72.70.+m; 74.20.-z.

COMING EVENTS

(An * indicates a previously listed event. Also see complete listing of upcoming conferences and workshops at our Web site http://www.iitap.iastate.edu/htcu/comevents.html.)

Aug. 29 - Sept. 3 1999: International Conference on the Applications of the Mossbauer Effect, Garmisch-Partenkirchen, Germany. Will focus on the communication of results of Mossbauer spectroscopy in all fields. Invited talks, oral contributions, and posters. For information, contact Klaus Achterhold, ICAME-99, Physikdepartment E17, TUM, D-85747 Garching, Germany; telephone +49 89 289 12559; telefax +49 89 289 12548; e-mail ICAME@physik.tu-muenchen.de; Web site http://www.physik.tu-muenchen.de/~icame.

Nov. 29 - Dec. 3, 1999: Materials Research Society Fall 1999 Meeting: Symposium Q -- Advances in Materials Problem Solving with the Electron Microscope, Boston, Mass. Contributions that make use of recent developments in elecron microscopy (rather than just "routine" imaging) to solve materials problems are solicited, in areas such as: structural metallic alloys (e.g., alloy development, phase transformations); structural and electronic ceramics, composites, and minerals; polymers, zeolites, catalysts, and fullerenes; microelectronic materials and electroluminescent materials; epitaxial and polycrystalline thin films and multilayers; and magnetic materials for permanent magnets and data storage. Abstract deadlines, June 7, 1999 (paper, fax, and e-mail submissions); June 21, 1999 (Web submissions). Contact Charles Allen, Argonne National Laboratory, Electron Microscopy Ctr.-HVEM-Tandem Facility, MSD 212/E211, 9700 South Cass Ave., Argonne, IL 60439; telephone (630) 252-4157; telefax (630) 252-4798 or -4298; e-mail allen@aaem.amc.anl.gov; conference Web site http://www.mrs.org/meetings/fall99/.

May 28 - June 2, 2000: International Conference on Transport Processes in Inorganic Materials: Fundamentals to Devices, Venice (Jesolo Beach), Italy. Objective is to discuss recent developments in microscopic mechanisms of transport in different inorganic materials; assess the role of transport in materials reactivity, synthesis, and processing; explore the transport mechanisms which affect materials properties and behavior under operating conditions; and exploit the role of transport processes in a number of advanced technologies of current or emerging interest. Papers are solicited in a several areas, including diffusion and transport in media of lower dimensionality, single-crystal growth, materials processing for HTS materials, and superconducting devices for high- and low-field applications. For information, contact CIMTEC- Transport Phenomena Conference, P.O. Box 174, I-48018 Faenza, Italy; telefax +39 0546 664138.

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.

The information contained herein is intended for limited distribution. Readers are expected to respect the rights of the authors.

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: MITRA@AMESLAB.GOV or MITRA@IASTATE.EDU

Project Director/Editor: Sreeparna Mitra Science Editor: John R. Clem High-Tc Update, Vol. 13, #11, June 1, 1999.