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, ONR, EPRI, and other agencies, organizations, and individuals.

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 from November 15, 1993, onward are also available in coded Word versions (BINHEX and RTF). (These versions preserve the Greek letters, special characters, accents, etc.) If you are interested in the alternate formats, contact the editor for information.

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:

Theory

A simple two-band model has been used by W. A. Atkinson (Indiana) et al. to examine the c-axis transport properties of the high-Tc superconductors in the underdoped case. The authors find that a pseudogap in the optical conductivity occurs naturally in this model, and that it can be identified as the minimum energy for an interband excitation. The pseudogap provides the energy scale for the upturn in the dc resistivity. The model also predicts a T^3 dependence for the low-temperature penetration depth, with a crossover to a linear T dependence at very low T.

Two related papers by W. A. Atkinson and J. P. Carbotte (McMaster) discuss further details of the c-axis transport of layered superconductors. In treating the c-axis optical conductivity, the authors find for weak interlayer coupling that it is preferable for electrons to travel along the c axis by making a series of interband transitions rather than to stay within a single, very narrow, band. The other preprint focuses on calculating the effect of interband transitions on the temperature dependence and the magnitude of the low- temperature c-axis penetration depth lambda_c(T).

The issue of the spin gap in the magnetic susceptibility chi"(q,omega) in high-Tc superconductors is discussed by J. Ranninger and J.-M. Robin (Grenoble) in the scenario of a mixture of localized tightly bound electron pairs in singlet states (bipolarons) and itinerant electrons. The authors find that as the temperature is lowered, antiferromagnetic correlations develop and produce a spin-wave-like spectrum in the subsystem of itinerant electrons. The onset of such coherence is accompanied by the opening of a pseudogap in the density of states of the electron subsystem whose temperature dependence is reflected in that of chi"(q,omega) near q = (pi,pi), where a spin gap is observed by inelastic neutron scattering and NMR.

A preprint by A. S. Alexandrov (Loughborough) considers the effect of Coulomb screening and reduced dimensionality on the condensation of localized bosons hybridized with fermions. The author shows that Cooper pairing of fermions via transitions into virtual bosonic (preformed- pair) states is impossible. However, the pairing of fermions is possible if real bosons are condensed at a very low temperature Tc.

A microscopic model of the evolution from antiferromagnetic insulator to superconductor on oxidation of the parent phase (CuO2)^2 sheets of a cuprate superconductor has been developed by G. I. Bersuker and J. B. Goodenough (Texas-Austin). The authors start with the assumption that strong electron-lattice interactions are dominant and thus give rise to a heterogeneous electronic distribution. As the temperature decreases, the model indicates first the formation of large, low-symmetry polarons, their condensation into a polaron liquid, their ordering into one- dimensional polaronic stripes, and finally superconductivity due to elastic coupling between polarons.

A recently developed model of the anisotropic gap, based on the Van Hove scenario, has been used by J. Bok and J. Bouvier (Paris) to calculate the tunneling density of states in high-Tc cuprates. The authors compare with experiment and find good agreement.

Vortices

A preprint by D. R. Nelson (Harvard) and A. Stern (Weizmann Institute) theoretically considers the winding of polymers around a repulsive cylindrical obstacle. The results apply also to the case of a vortex- line liquid surrounding a superconducting rod containing an array of strongly pinned vortices parallel to the axis. Application of a current along the rod would induce the vortices in the surrounding line liquid to wind around the rod.

The low-temperature dynamics of an elastic manifold driven through a random medium has been studied theoretically by V. M. Vinokur (Argonne). For driving forces well below the zero-temperature depinning force, the manifold advances via thermally activated hops over the energy barriers separating favorable metastable states. The author develops a scaling theory of the thermally activated dynamics (creep).

Large-scale parallel simulations have been used by C. J. Olson (Michigan) et al. to compute the motion of vortices during avalanches triggered by small field increases. The authors find that experimentally observable voltage bursts correspond to pulsing vortex movement along branched channels or winding chains, and relate vortex- flow images to features of statistical distributions. As the pin density is increased, a crossover occurs from interstitial motion in narrow easy-flow winding channels with a narrow distribution of avalanche sizes, to pin-to-pin motion in broad channels with a broad distribution of avalanche sizes.

The dynamics of vortices driven by transport current in two-dimensional disordered type-II superconductors has been studied by Y. Enomoto and S. Maekawa (Nagoya) using Langevin-dynamics simulations. The authors explore the electric field E induced as a function of the transport current density J and find that the combined effect of random impurities and current-induced vortex-antivortex pair creation leads to dynamical scaling behavior of E vs. J near a certain critical temperature.

Measurements of magnetic flux noise in YBa2Cu3O7-d superconducting rings and disks having a large range of superconducting transition temperatures are reported by S.A.L. Foulds (Birmingham) et al. In the absence of an applied magnetic field, the magnetic noise in rings close to the transition results from flux jumps of single flux quanta, and the behavior can be explained in terms of thermal activation between the lowest few metastable states of a superconducting loop containing a single Josephson junction. In the presence of a small applied magnetic field, the sharp quantum jumps disappear, and the behavior can be explained by modeling the ring as a fixed inductance with a temperature- dependent resistance directly proportional to the applied field.

The magnetic flux structures in YBa2Cu3O7-d single-crystal plates during their remagnetization in unidirectional and rotating magnetic fields have been imaged by V. K. Vlasko-Vlasov (Argonne and ISSP-Chernogolovka) et al. using magneto-optical techniques. Bending of flux lines results in the formation of flux-free cylinders (Meissner holes) surrounded by closed vortex loops.

YBa2Cu3O7-d

There has been recent progress in producing highly oriented YBa2Cu3O7-d (Y-123) thick films over buffer layers on metallic substrates. One method for accomplishing this is to (a) start with Ni-alloy (Hastelloy) strips, (b) use ion-beam-assisted deposition (IBAD) to deposit biaxially textured yttria-stabilized zirconia (YSZ) buffer layers on the strips, and (c) deposit epitaxial Y-123 films on the YSZ. Another method is to (a) use a technique called rolling-assisted, biaxially textured substrates (RABiTS) to produce polycrystalline Ni strips consisting of many grains with nearly the same orientation, (b) deposit buffer layers on the strips, and (c) deposit epitaxial Y-123 films on the top buffer layers. Both processes have been shown to yield Y-123 conductors with Jc in excess of 10^5 A/cm^2 at 77 K even in applied magnetic fields of several T. An important question, however, is whether the metallic substrates of such tapes lead to unacceptably high eddy-current losses under ac conditions.

To investigate this question, K.-H. Mueller (CSIRO) has analytically calculated the eddy-current ac power loss in the metal and the hysteresis loss in the superconductor of a metal-superconductor tape in the low-frequency limit. He studied the cases where (a) an ac magnetic field is applied perpendicular to the tape, (b) an ac field is applied parallel to the tape, and (c) an ac current is applied to the tape. He found that the losses are smallest in case (b), while the losses in cases (a) and (c) show an approximate scaling. In cases (a) and (c), the eddy-current loss becomes important in high ac fields or at high ac currents, respectively, while in case (b), the eddy-current loss becomes important at high fields and at low fields but is less important at moderately strong fields. The author concludes, however, that because of the high resistivity of the Hastelloy, the eddy-current loss of a typical Hastelloy/Y-123 flexible tape can be neglected at frequencies below 100 Hz for all practical ac applications, and only the hysteresis loss in the superconductor is of importance.

The field-induced pinning effect in Nd1+xBa2-xCu3O7-d single crystals grown by the traveling-solvent floating-zone (TSFZ) method using feed rods of Nd[1+alpha]Ba[2-alpha]Cu3O7[-d] (alpha = 0 and 0.1) has been studied by K. Kuroda et al. (SRL-ISTEC). The field dependence of Jc was found to depend on the composition: At 77 K, the sample with alpha = 0 exhibited a peak in Jc at 1-2 T, while the sample with alpha = 0.1 had a Jc that decreased monotonically with magnetic field. As noted by the authors, the results support the idea that the field-induced enhancement of Jc is caused by finely dispersed weak superconducting regions where the Ba site is substituted by Nd ions in the stoichiometric Nd-123 matrix.

The thermal conductivity Kappa of YBa2Cu3O6.9 has been measured by R. Gagnon et al. (McGill) along the a and b axes of detwinned single crystals. Both Kappa_a and Kappa_b showed the usual peak below Tc = 93.8 K, but a clear additional contribution to the b-axis conduction was found to set in well below Tc. The difference Kappa_b - Kappa_a exhibits a peak very similar to the plane conductivity Kappa_a but with an onset temperature of 55 K. According to the authors, this suggests that the CuO chains give rise to a sudden growth in superfluid density at that temperature, as predicted by models of single-electron tunneling between chains and planes.

The normalized logarithmic decay rate S(T,H) of the magnetization of YBa2Cu3O7-d single crystals and epitaxial thin films has been studied experimentally by I. Isaac and J. Jung (Alberta). The authors conclude that a divergence of S(T,H) near Tc could stem from filamentary superconducting structures caused, for example, by phase separation.

A physico-chemical model for the growth of melt-textured YBa2Cu3O7- d/Y2BaCuO5 (123/211) composites under isothermal conditions, taking into account the effect of repulsion between the front and 211 particles, is proposed in a paper by N. Vandewalle et al. (Liege). The results are in good agreement with experimental observations.

Magnetization loops of QMG-processed (quench and melt growth) bulk YBa2Cu3O7-d have been measured by G. C. Han (Tohoku) et al. at 4.2 K in fields up to 23 T using a new vibrating sample magnetometer (VSM) combined with a hybrid magnet. No flux jumps were observed, although magnetization loops for the same sample, as measured using a conventional VSM, showed flux jumps at an even lower field-sweep rate.

A preprint by A. Diaz et al. (Santiago de Compostela) reports measurements of the current-voltage characteristics (CVC) of granular YBa2Cu3O7-d samples and interprets these in terms of effective-medium theory. The theory successfully predicts that the CVC slope of nontextured granular YBa2Cu3O7-d should be equal to approximately one- third of the normal-state resistivity extrapolated to zero temperature.

Bi Cuprates

As reported by Q. Y. Hu et al. (Wollongong), a new mechanical deformation process has been developed to fabricate high-quality high- temperature superconducting Ag-sheathed Bi-2223 tapes. In this process, the rolling step of the powder-in-tube technique is replaced by a supercold rolling step, carried out in liquid nitrogen to harden the Ag sheath. The authors found the critical current density of the resulting tapes to be significantly enhanced by the supercold rolling process. Microstructural observations of the tapes revealed that the supercold rolled tapes had higher mass density and better grain alignment than room-temperature-rolled tapes, and these effects evidently are responsible for the increased critical current density.

Five preprints by K.-H. Mueller (CSIRO) et al. report the separation of intergranular and intragranular critical currents and the determination of ac losses in Ag-sheathed (Bi,Pb)2Sr2Ca2Cu3O10+d [(Bi,Pb)-2223] superconducting tapes. The critical current separation was accomplished by using SQUID magnetometry to compare the magnetic moments of unbent and bent tapes. The authors demonstrated that the magnetization of bent tapes arose solely from intragranular currents; bending caused grain- boundary microcracking, which reduced the intergranular currents to zero. The ac losses were determined using a lock-in amplifier. The authors found that if the ac power loss is to be measured with an accuracy better than 10% down to an amplitude of 0.1 I_c, the phase- angle error must be less than +-0.004 degree.

Yttrium-doped Bi2Sr2CaCu2O8+d (Bi-2212) superconducting single crystals with a nominal Sr-deficient composition of Bi2(Sr1.6Y0.4)CaCu2Oy have been investigated by X. F. Zhang (Antwerp and Beijing) et al. using transmission electron microscopy (TEM). In addition to the normal Y- doped phase whose structure is similar to that of the 2212 phase, the authors found a new phase which is also based on the 2212 structure but has a 2a x 2b superstructure superimposed on the intrinsic modulation structure. Regions containing the normal Y-doped 2212 phase and the new phase alternate along the a direction, with interface planes parallel to the (100) lattice planes.

A strong peak effect has been observed by X. L. Wang et al. (Wollongong) in both high-Tc (86 K) and oxygen-underdoped (Tc = 76 K) spiral-grown crystals of Bi2Sr2CaCu2O8+d (Bi-2212) between 20 K and 40 K. The authors conclude that this effect arises from edge barriers due to growth spirals and not from screw dislocations or oxygen vacancies.

Tl Cuprates

A preprint by L. Ozyuzer (IIT and Argonne) et al. reports measurements of the tunneling density of states obtained from tunnel junctions on single crystals of Tl2Ba2CuO6+d (Tl-2201) (Tc ~~ 91 K) using a mechanical, point-contact method. SIN and SIS' junctions were obtained using Au and Nb tips, respectively. The authors found reproducible tunneling conductances with sharp, well-defined energy-gap structure and a cusp-like feature at zero bias. The conductances can be fit to a density of states obtained from a tight-binding band structure and a superconducting order parameter with d_[x^2-y^2] symmetry.

As shown by J. L. Wagner (Argonne and North Dakota) et al. using x-ray diffraction, the superconducting and structural properties of Tl2Ba2CuO6+d (Tl-2201) depend on at least two defects. The Tl/Cu ratio used during synthesis determines the concentration of a defect that is likely to be Cu substitution on the Tl site. The structure exhibits either a smaller orthorhombic strain or tetragonal symmetry for high concentrations of this defect. An oxygen interstitial defect in the Tl- O double layer has a more pronounced effect on Tc and allows the compound to be overdoped as the concentration of this defect increases.

The magnetic properties and critical currents in Tl2Ba2Ca2Cu3O10 (Tl- 2223) and (Tl, Pb)(Sr,Ba)2Ca2Cu3O9 (Tl-1223) single crystals have been investigated by G. Brandstaetter (Atominstitut-Wien) et al. using SQUID magnetometry in fields parallel to the c axis up to 8 T. The samples were subjected to sequential reactor neutron irradiation up to a fluence of 24 x 10^[21] m^[-2] (E > 0.1 MeV). The authors found Jc in Tl-2223 to be strongly enhanced by radiation-induced defects, e.g., by a factor of 52 at 40 K and 1 T. In Tl-1223, the critical current densities were moderately enhanced, and the irreversibility line, which is at the same position or even higher than that of Y-123, was moderately shifted to higher fields and temperatures after irradiation.

Other Cuprates

Measurements of the spin shift [17]^K_s, which is directly proportional to the spin susceptibility chi_s(T) of the CuO2 planes, have been carried out by J. Bobroff (Orsay) et al. for the [17]^O NMR line in HgBa2CuO4+d (Hg-1201). In the underdoped regime, chi_s is found to extrapolate to zero at T >= 0. This indicates that a pseudogap opens at T* > Tc, as in YBa2Cu3O6.6, in disagreement with recent theories based on La2-xSrxCuO4 NMR data. The pseudogap features therefore cannot be explained in terms of a magnetic coupling between CuO2 planes in bilayer systems. The pseudogap is a general feature of the underdoped cuprates, whatever the number of layers in the unit cell.

A preprint by A. Fukuoka et al. (SRL-ISTEC) reports the lattice parameters, Tc, resistivity, and thermoelectric power in samples of single-phase HgBa2CaCu2O6+d (Hg-1212) and HgBa2Ca2Cu3O8+d (Hg-1223), for which the oxygen content and Cu valence were determined by iodometric titration. The authors conclude that the Hg-1223 sample with the highest Tc of 135 K is almost optimally doped. The compounds Hg-1201, Hg-1212, and Hg-1223 all exhibit their maximum Tc values at the same nominal Cu valence of approximately 2.20, which is close to that of other high-Tc cuprate superconductors. This coincidence of the Cu valence for optimally doped states suggests that the simple ionic model where each excess oxygen in the HgOd charge reservoir supplies two holes is appropriate in these Hg-12(n-1)n samples.

A preprint by X.-J. Wu et al. (SRL-ISTEC) reports the observation of several new intergrowth phases in Hg-Tl-Ba-Ca-Cu-O compounds by transmission electron microscope (TEM) observations.

The magnetic properties of the CuO2 planes in the low-temperature- tetragonal (LTT) phase of Eu-doped La2-xSrxCuO4 as determined by ESR of Gd spin probes are reported by V. Kataev (Kazan) et al. The data indicate that at particular levels of Sr and Eu doping, the frequency of the antiferromagnetic fluctuations in the LTT phase decreases by about three orders of magnitude at low temperatures. No static magnetic order was found for T >= 8 K, in contrast to the observation by neutron scattering of stripe ordering of spins below 50 K in a Nd-doped La2- xSrxCuO4 single crystal.

A preprint by O. V. Dolgov (Moscow) et al. reports that the normal-state response of La2-xSrxCuO4 is consistent with a simple multi-component model based on free carriers with a strong electron-phonon interaction, localized polaronic states near 0.15 eV, and a mid-infrared band at 0.5 eV.

Films

A preprint by A. Gurevich (Wisconsin) and E. H. Brandt (MPI-Stuttgart) reports analytic and numerical calculations of the ac susceptibility and nonlinear electromagnetic response of thin superconducting strips and disks of constant thickness in a perpendicular time-dependent magnetic field B_a(t) = B_0cos[omega*t], taking into account the strong nonlinearity of the voltage-current characteristics below the irreversibility line.

Persistent photoconductivity has been observed by A. Hoffmann (UC-San Diego) et al. in thin-film YBa2Cu3O7-d bicrystal grain-boundary Josephson junctions. Upon illumination of these junctions, the normal- state resistance decreased and the critical current increased, showing that the grain boundary in these films consists of oxygen-depleted YBa2Cu3Ox. A comparison with the persistent photoconductivity in oxygen-depleted YBa2Cu3Ox thin films implies an average oxygen content of x = 6.6+-0.1 for the grain boundary.

Low-temperature scanning electron microscopy (LTSEM) with electron-beam- induced voltage contrast has been used by S.A.L. Foulds (Birmingham) et al. to investigate the quality of current flow in thin-film YBa2Cu3O7-d (YBCO) tracks deposited over meanders in SrTiO3 substrates.

A preprint by Y. P. Li et al. (TCSUH) reports studies of Ag doping of YBa2Cu3O7-d thin films (~0.43 micrometer and ~0.95 micrometer) by 800- keV Ag+ implantation at room temperature and elevated temperatures (450^oC, 650^oC, and 780^oC). The authors studied the conditions under which superconductivity can be maintained after implantation.

The properties of a bolometer in the form of a YBCO thin-film microbridge are reported by H. Z. Chen et al. (National Sun Yat-Sen). With a bias current of 8 mA at 77.35 K, the responsivity of the bolometer reached as high as 2.3 x 10^3 V/W at all wavelengths in the range 0.633 micrometer to 3.5 micrometers.

A preprint by Y. Ishimaru et al. (SRL-ISTEC) reports investigations of a Bi2Sr2CaCu2O8+d (Bi-2212) Josephson junction consisting of a (110)- oriented grain surrounded by (001)-oriented grains. Hysteretic I-V characteristics were observed, indicating the presence of intrinsic Josephson junctions between stacked CuO2 double layers along the c direction.

Other Activities

Critical state magnetization loops in long superconductors with cross sections in the shape of a rectangle or circle have been calculated by A. B. Riise et al. (Oslo), using two models for the field dependence of Jc(B).

The best model system to date for a spin-1/2 two-dimensional square- lattice Heisenberg antiferromagnet is the compound Sr2CuO2Cl2, which contains flat CuO2 sheets separated by two nonmagnetic SrCl layers. A preprint by D. Vaknin et al. (Ames Lab/Iowa State) reports neutron- scattering and magnetic susceptibility results for a single crystal of this compound.

Overviews

An overview (in Russian) by K. S. Alexandrov and B. V. Beznosikov (Krasnoyarsk) considers structures of the known perovskite-like crystals as slabs containing n layers (n = 1-infinity) of corner-linked octahedra BX6, pyramids BX5, or quadratic nets BX4 (B = cation, X = anion), intergrowing with intermediate blocks of different types. The authors classify the known structures into a hierarchy of stoichiometric, cation-deficient, and anion-deficient perovskite-like crystals and identify systems where the synthesis of new layered crystals, including high-temperature superconductors, might be possible (116 refs.).

A review of the effects of microwave radiation on superconducting devices and the superconducting state, with a focus on critical-current and superconducting-gap enhancement, has been prepared by E. D. Dahlberg (Minnesota) and I. K. Schuller (UC-San Diego). The authors present evidence that there is at least one mechanism for critical-current enhancement that does not involve an increase in the energy gap (26 refs.).

A brief review of the state of the art of transport in the high-Tc superconductors, including electrical resistivity, thermoelectric power (Seebeck effect), and thermal conductivity has been prepared by M. Ausloos (Liege). The author focuses on the interpretation of magnetic- field-induced changes in the corresponding transport coefficients (18 refs.).

Ph.D. Thesis

Applications of in-plane-aligned a-axis-oriented YBa2Cu3O7-d (YBCO) based multilayers for trilayer Josephson junctions and for the characterization of the anisotropy of YBCO were studied in the Ph.D. thesis of I. Takeuchi (Maryland). From the magnetic-field dependence of the Josephson critical currents of vertical YBCO/Au/Ag/PbIn junctions, the author was able to determine the London penetration depths lambda_b = (2,000+-200) Angstroms and lambda_c = (1.2+-0.2) mm at 4.2 K (140 refs.).

Contributed by John R. Clem

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.

Ajay and R. S. Tripathi, "Role of Interlayer Interactions on Transition Temperature in High-Tc Cuprate Superconductors." To be published in Physica C (in press). #250 Condensed Matter Group, National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi 110012, INDIA; telefax +91 11 575 2678; e-mail ajay@arjun.sirnetd.ernet.in. 74.62.Bf; 74.80.Dm; 74.20.Fg.

V. L. Aksenov, A. M. Balagurov, V. V. Sikolenko, V. G. Simkin, V. A. Alyoshin, E. V. Antipov, A. A. Gippius, D. A. Mikhailova, S. N. Putilin, and F. Bouree, "Precision Neutron Diffraction Study of the High-Tc Superconductor HgBa2CuO4+d." To be published in Phys. Rev. B. Contact A. M. Balagurov, Frank Lab of Neutron Physics, Joint Institute for Nuclear Research, 141980 Dubna, Moscow Region, RUSSIA; telephone +7 09621-65803; telefax +7 09621-65882; e-mail bala@nf.jinr.ru.

K. S. Aleksandrov and B. V. Beznosikov, "Hierarchy and Architecture of Perovskite-Like Crystals." Preprint #769; to be published in Perovskite-Like Crystals (Nauka, Novosibirsk, Russia, 1997). L. V. Kirensky Institute of Physics, Siberian Branch of the Russian Academy of Sciences, Krasnoyarsk 660036, RUSSIA; e-mail aleks@iph.krasnoyarsk.su. Preprint in Russian.

A. S. Alexandrov, "Condensation of Charged Bosons Hybridized with Fermions." To be published in Physica C (in press). Department of Physics, Loughborough University of Technology, Loughborough LE11 3TU, UNITED KINGDOM; telefax +44 1509 223986; e-mail asa21@cus.cam.ac.uk. 74.20.-z; 67.20.+k.

W. A. Atkinson and J. P. Carbotte, "The c Axis Optical Conductivity of Layered Systems in the Superconducting State." Submitted to Phys. Rev. B. Department of Physics, Swain Hall W 117, Indiana University, Bloomington, IN 47405; e-mail atkinson@gibbs.physics.indiana.edu; preprint also available at cond-mat@xxx.lanl.gov (#9701028). 74.25.Nf; 74.25.Jb; 74.72.-h.

W. A. Atkinson and J. P. Carbotte, "Effect of Interband Transitions on c-Axis Penetration Depth of Layered Superconductors." Submitted to Phys. Rev. B. Department of Physics, Swain Hall W 117, Indiana University, Bloomington, IN 47405; e-mail atkinson@gibbs.physics.indiana.edu; preprint also available at cond-mat@xxx.lanl.gov (#9612058). 74.25.Nf; 74.25.Jb; 74.72.-h.

W. A. Atkinson, W. C. Wu, and J. P. Carbotte, "Manifestations of the Pseudogap in the c Axis Properties of High Tc Superconductors." Submitted to Phys. Rev. Lett. Department of Physics, Swain Hall W 117, Indiana University, Bloomington, IN 47405; e-mail atkinson@gibbs.physics.indiana.edu; preprint also available at cond-mat@xxx.lanl.gov (#9701029). 74.25.Nf; 74.25.Jb; 74.72.-h.

M. Ausloos, "Electrical and Thermal Magneto-Transport in the Mixed State of High Tc Superconductors." To be published in the Proc. of the NATO Adv. Res. Workshop on Mic. Phys. and Tech., Sozopol, Bulgaria, Sept. 30- Oct. 5, 1996. SUPRAS, Institute of Physics, B5, University of Liege, Sart Tilman, B-4000 Liege, BELGIUM; telephone +32 4 366 3752; telefax +32 4 366 2990; e-mail ausloos@gw.unipc.ulg.ac.be; Web site http://www.phe.ulg.ac.be.

V. Beilin, A. Goldgirsh, and M. Schieber, "Deformation-Dominated Texturing of Superconducting Filament in OPIT-Fabricated Bi(Pb)SCCO- 2223/Ag Composite Tapes." Presented at the Appl. Supercond. Conf. (ASC'96), Pittsburgh, PA, Aug. 25-30, 1996; to be published in IEEE Trans. Appl. Supercond. Graduate School of Applied Science, Hebrew University of Jerusalem, Jerusalem, ISRAEL; telefax +972 2 6586414; e- mail beilin@shum.cc.huji.ac.il.

Jorge Berger and Jacob Rubinstein, "Design for the Detection of the Singly-Connected Superconducting State." Submitted to Phys. Rev. B. Department of Physics, Technion, 32000 Haifa, ISRAEL; e-mail phr76jb@aluf.technion.ac.il; preprint also available at cond-mat@xxx.lanl.gov (#9612141). 74.60.Ec.

Gennadi I. Bersuker and John B. Goodenough, "Large Low-Symmetry Polarons of the High-Tc Copper Oxides: Formation, Mobility and Ordering." To be published in Physica C (in press). Contact John B. Goodenough, Center for Materials Science and Engineering, University of Texas at Austin, Austin, TX 78712; telefax (512) 471-7681; e-mail jgoodenough@mail.utexas.edu.

Howard A. Blackstead and John D. Dow, "Definitive Test of Spin- Fluctuation Pairing: Pair Breaking." Submitted to Physica C. Department of Physics, University of Notre Dame, Notre Dame, IN 46556; telephone (219) 631-7078; telefax (219) 631-5952; e-mail blackstd@rems1.phys.nd.edu.

J. Bobroff, H. Alloul, P. Mendels, V. Viallet, J.-F. Marucco, and D. Colson, "[17]^O NMR Evidence for a Pseudogap in the Monolayer HgBa2CuO4+d." Submitted to Phys. Rev. Lett. Laboratoire de Physique des Solides, URA2 CNRS, F-91405 Orsay Cedex, FRANCE. 74.25.Nf; 74.72.Gr.

J. Bok and J. Bouvier, "Tunneling in Anisotropic Gap Superconductors." To be published in Physica C (in press). Laboratoire de Physique du Solide UPR 5 CNRS, ESPCI, 10 rue Vauquelin, F-75231 Paris Cedex 05, FRANCE; telefax +33 1 4079 4451; e-mail jacqueline.bouvier@espci.fr. Key words: superconductivity, anisotropic gap, Van Hove singularities, tunneling spectroscopy. 74.20.-z; 74.20.Fg; 74.50.+r.

G. Brandstaetter, F. M. Sauerzopf, and H. W. Weber, "Magnetic Properties and Critical Currents in Tl-Based High-Tc-Superconducting Single Crystals." To be published in Phys. Rev. B. Atominstitut der OEsterreichsichen Universitaeten, A-1020 Wien, AUSTRIA; H. W. Weber's e- mail weber@ati.ac.at. 74.60.Ge; 74.60.Jg; 74.72.Fq.

H. Z. Chen, T. C. Chow, M. T. Hong, T. L. Lin, K. S. Lin, Y. F. Cheng, Y. C. Chen, and H. Chou, "The Broad Band Optical Detection of Precipitational Free YBCO Thin Films." To be published in Physica C (in press). Contact H. Chou, Department of Physics, National Sun Yat-Sen University, Kaohsiung, Taiwan, REPUBLIC OF CHINA.

E. Dan Dahlberg and Ivan K. Schuller, "Gap Enhancement in Superconductors: Where Did It Go?" To be published in 35 Years of Condensed Matter and Related Physics, Proc. of the Raymond L. Orbach Symp., Univ. of California, Riverside, CA, March, 1995, edited by D. W. Hone. School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455.

A. Diaz, J. Maza, and F. Vidal, "Anisotropy and Structural Defect Contributions to Percolative Conduction in Granular Copper Oxide Superconductors." To be published in Phys. Rev. B. LAFIMAS, Departamento de Fisica de la Materia Condensada, Universidad de Santiago de Compostela, E-15706 Santiago de Compostela, SPAIN; J. Maza's telephone +34 81 56 31 00; telefax +34 81 52 06 76; e-mail fmmaza@usc.es.

Oleg V. Dolgov, Holger J. Kaufmann, Ekhard K.H. Salje, and Yoad Yagil, "Evidence for Strong Electron-Phonon Coupling and Polarons in the Optical Response of La2-xSrxCuO4." Contact Holger J. Kaufmann, Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UNITED KINGDOM; telephone +44 1223 33 34 11; telefax +44 1223 33 34 50; e-mail hjk22@cus.cam.ac.uk; preprint also available at cond-mat@xxx.lanl.gov (#9612131). 74.20.De; 74.25.Fy; 74.25.Gz; 74.72.Dn.

Yoshihisa Enomoto and Sadamichi Maekawa, "Dynamical Scaling Behavior of Current-Electric Field Characteristics in Two-Dimensional Disordered Superconductors." To be published in Physica C (in press). Department of Physics, Nagoya Institute of Technology, Gokiso, Nagoya 466, JAPAN; e-mail eno@ks.kyy.nitech.ac.jp.

S.A.L. Foulds, J. S. Abell, Dae-Joon Kang, and E. J. Tarte, "Investigation of Critical Currents in YBCO Tracks over Steps in SrTiO3 Substrates Using Low Temperature SEM Beam Induced Voltage Contrast." Presented at the Appl. Supercond. Conf. (ASC'96), Pittsburgh, PA, Aug. 25-30, 1996; to be published in IEEE Trans. Appl. Supercond. Superconductivity Research Group, School of Metallurgy and Materials, University of Birmingham, Birmingham B15 2TT, UNITED KINGDOM; telephone +44 121 414 5170; telefax +44 121 414 5232; e-mail s.a.l.foulds@bham.ac.uk.

S.A.L. Foulds, J. Smithyman, G. F. Cox, C. M. Muirhead, and R. G. Humphreys, "Magnetic Flux Noise in Superconducting Rings and Discs Close to the Superconducting Transition." To be published in Phys. Rev. B. Superconductivity Research Group, School of Metallurgy and Materials, University of Birmingham, Birmingham B15 2TT, UNITED KINGDOM; telephone +44 121 414 5170; telefax +44 121 414 5232; e-mail s.a.l.foulds@bham.ac.uk. 74.25.Ha; 74.40.+k; 74.76.Bz.

Masashi Fujiwara, Masahiro Nagae, Yoshihiro Kusano, Tatsuo Fujii, and Jyun Takada, "Li Doping to the 2212 Phase in the Bi-Sr-Ca-Cu System." To be published in Physica C (in press). Department of Applied Chemistry, Faculty of Engineering, Okayama University, 3-1-1 Tsushima- naka, Okayama 700, JAPAN; telefax +81 86 255 7900; e-mail jtakada@cc.okayama-u.ac.jp. Key words: Bi-2212 phase, Li-doping, single phase, formation process, Tc, solid-state reaction. 74.72.-h.

A. Fukuoka, A. Tokiwa-Yamamoto, M. Itoh, R. Usami, S. Adachi, and K. Tanabe, "Dependence of Tc and Transport Properties on the Cu Valence in HgBa2Can-1CunO2(n+1)+d (n=2,3) Superconductors." 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; telephone +81 3 3536-5703 through -5705; telefax +81 3 3536-5714 or -5717. 74.25.-q; 74.62.-c; 74.72.Jt.

Robert Gagnon, Song Pu, Brett Ellman, and Louis Taillefer, "Anisotropy of Heat Conduction in YBa2Cu3O6.9: A Probe of Chain Superconductivity." Contact Louis Taillefer, Department of Physics, McGill University, 3600 University Street, Montreal, Quebec, CANADA H3A 2T8; telephone (514) 398-6476 or -6485; telefax (514) 398-6526 or -8434; e-mail louis@physics.mcgill.ca. Key words: YBCO, thermal conductivity, CuO chains. 74.72.Bk; 74.25.Fy.

K. Ganesh, R. J. Topare, N. K. Sahuji, S. S. Shah, P. Venugopal Reddy, "Elastic Behavior of Calcium-Doped Y-124 High Tc Superconducting Materials." To be published in Physica C (in press). Contact P. Venugopal Reddy, Department of Physics, College of Science, Osmania University, Hyderabad 500 007, INDIA; telefax +91 40 86 6020.

Haranath Ghosh, S. N. Behera, S. K. Ghatak, and D. K. Ray, "Mutual Influence of Structural Distortion and Superconductivity in Systems with Degenerate Bands." To be published in Physica C (in press). Institute of Physics, Bhubaneswar 751 005, INDIA.

F. J. Gotor, P. Simon, N. Pellerin, P. Odier, and Ph. Monod, "Paramagnetic Cu^[2+] Centers in the Oxycarbonate Phase YBa2Cu2.95(CO3)0.35 O6.6 Probed by EPR and Magnetic Susceptibility." To be published in J. Phys. Chem. Solids. Contact P. Odier, Centre de Recherches sur la Physique des Hautes Temperatures-CNRS, 1D, Avenue de la Recherche Scientifique, F-45071 Orleans Cedex 2, FRANCE; telephone +33 238 515525; telefax +33 238 638103; e-mail odier@cnrs-orleans.fr. Key words: superconductors, electronic paramagnetic resonance (EPR), sol-gel growth.

J.-C. Grivel, R. E. Gladyshevskii, E. Walker, and R. Fluekiger, "Effect of Air-Annealing on the Solubility of Pb in the Bi2Sr2CaCu2O8+d Phase." To be published in Physica C (in press). Departement de Physique de la Matiere Condensee, Universite de Geneve, 24 quai Ernest-Ansermet, CH- 1211 Geneve 4, SWITZERLAND.

A. Gurevich and E. H. Brandt, "ac Response of Thin Superconductors in the Flux-Creep Regime." Submitted to Phys. Rev. B. Applied Superconductivity Center, University of Wisconsin, Madison, WI 53706; telephone (608) 263-2549; telefax (608) 263-1087; e-mail gurevich@coefac.engr.wisc.edu. 74.60.Ge; 74.60.Jg; 74.25.Nf.

G. C. Han, K. Watanabe, S. Awaji, N. Kobayashi, and K. Kimura, "Magnetization and Instability in Melt-Textured YBa2Cu3O7 at Low Temperature and High Fields up to 23 T." To be published in Physica C (in press). Research Institute of Superconductivity, Faculty of Engineering, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, JAPAN. 74.60.Ge; 74.60.Jg.

A. Hoffmann, Ivan K. Schuller, A. Gilabert, M. G. Medici, F. Schmidl, and P. Seidel, "Persistent Photoconductivity in High Tc Grain Boundary Josephson Junctions." Submitted to Appl. Phys. Lett. Physics Department 0350, University of California, 9500 Gilman Drive, La Jolla, CA 92093-0350; e-mail hoffmann@ucsd.edu.

Q. Y. Hu, H. K. Liu, and S. X. Dou, "Fabrication of the Ag Sheathed Bi2223 Tape with Supercold Rolling Process." To be published in Physica C. Centre for Superconducting and Electronic Materials, University of Wollongong, Wollongong, NSW 2522, AUSTRALIA; telephone +61 42 21-3022 or -4566; telefax +61 42 21-4577; e-mail qingyu@uow.edu.au.

I. Isaac and J. Jung, "Origin of the Fast Magnetic Relaxation Close to Tc in Y1Ba2Cu3O7-d." To be published in Phys. Rev. B. Department of Physics, University of Alberta, Edmonton, Alberta, CANADA T6G 2J1.

Yoshihiro Ishimaru, Jianguo Wen, Tadashi Utagawa, Naoki Koshizuka, and Youichi Enomoto, "Lateral Type Intrinsic Josephson Junctions Using (110) Oriented Grains in Bi2Sr2Ca1Cu2O8+d Films." To be published in Jpn. J. Appl. Phys. Superconductivity Research Laboratory, International Superconductivity Technology Center (ISTEC), 10-13 Shinonome 1-chome, Koto-ku, Tokyo 135, JAPAN; telephone +81 3 3536-5703 through -5705; telefax +81 3 3536-5714 or -5717. Key words: Bi2Sr2Ca1Cu2O8+d, (110) oriented grain, intrinsic Josephson junction, hysteresis, TEM.

J. Karpinski, H. Schwer, G. I. Meijer, K. Conder, E. M. Kopnin, and C. Rossel, "High-Oxygen-Pressure Synthesis, Structure and Properties of the Infinite-Chain Compound Sr0.73CuO2." To be published in Physica C (in press). Laboratorium fuer Festkoerperphysik, Eidgenoessische Technische Hochschule Zurich, CH-8093 Zurich, SWITZERLAND.

V. Kataev, B. Rameev, B. Buechner, M. Huecker, and R. Borowski, "Slow Antiferromagnetic Dynamics in the Low Temperature Tetragonal Phase of La2-xSrxCuO4 as Revealed by ESR of Gd Spin Probes." To be published in Phys. Rev. B. II. Physikalisches Institut, Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln, GERMANY; e-mail kataev@colorix.ph2.uni-koeln.de; preprint also available at cond-mat@xxx.lanl.gov (#9612011). 74.25.Ha; 74.72.Dn; 76.30.Kg.

W. Kempinski, P. Scharff, J. Stankowski, L. Piekara-Sady, and Z. Trybula, "EPR of Fullerene Ions and Superconductivity in K-Fullerides at Low Doping Levels." To be published in Physica C (in press). Institute of Molecular Physics, Polish Academy of Sciences, ul. Krotoszynska 63- 430 Odolanow, Poznan, POLAND. Key words: fullerene, fullerides, superconductivity, EPR.

Chan-Joong Kim, Yi-Sung Lee, Hyun-Soon Park, Il-Hyun Kuk, Tae-Hyun Sung, Jin Joong Kim and Gye-Won Hong, "Oxidation Induced Formation of a-b Planar Defects in Melt-Texture YBa2Cu3O7-y Containing Y2BaCuO5 Inclusions." To be published in Physica C. Superconductivity Research Laboratory, Korea Atomic Energy Research Institute, P.O. Box 105, Yusung, Taejon 305-600, SOUTH KOREA; telephone +82 42 868 8908; telefax +82 42 862 5496; e-mail super9@nanum.kaeri.re.kr.

Yong-Jihn Kim, "Pairing in the Bogoliubov-de Gennes Equations." To be published in Int. J. Mod. Phys. B. Department of Physics, Korea Advanced Institute of Science and Technology, Taejon 305-701, KOREA; e- mail yjkim@julie.kaist.ac.kr; preprint also available at cond-mat@xxx.lanl.gov (#9701102). 05.30.-d; 74.20.-z; 74.90.+n.

Jens Kisker and Heiko Rieger, "Bose Glass and Mott Insulator Phase in the Disordered Boson Hubbard Model." Institut fuer Theoretische Physik, Universitaet zu Koeln, D-50937 Koeln, GERMANY; Heiko Rieger's e-mail heiko@hlrz23.hlrz.kfa-juelich.de; preprint also available at cond-mat@xxx.lanl.gov (#9612027). 67.40.-w; 74.20.Mn.

N. Kristoffel, "Suppression of the Superconductivity Tc by Structural Ordering in a Two-Channel Interband Model." To be published in Physica C (in press). Institute of Physics, EE2400 Tartu, Riia 142, ESTONIA; telefax +372 7 383 033; e-mail kolja@park.tartu.ee. Key words: superconductivity temperature, structural transition, three-band model. 74.20.Mn; 74.62.Bf; 77.80.Bh.

K. Kumagai, Yu. V. Piskunov, A. Yu. Yakubovskii, S. V. Verkhovskii, A. P. Gerashenko, Yu. I. Zhdanov, K. N. Mikhalev, I. V. Sagaradze, Eu. Yu. Medvedev, S. M. Cheshnitskii, and R. N. Pletnev, "Local Distortions in the BiO6-Octahedra Sublattice of BaPbxBi1-xO3 as Seen by [137]^Ba NMR/NQR." To be published in Physica C (in press). Contact S. V. Verkhovskii, Institute of Metal Physics, Russian Academy of Sciences, Kovalevskaya str. 18, Ekaterinburg 620219, RUSSIA; telefax +7 343 244 5244; e-mail verkhovskii@ifm.ural.ru. Key words: nuclear magnetic resonance (NMR), nuclear quadrupolar resonance (NQR), BaPbxBi1-xO3, BiO6-octahedra tilting.

Kiyoshi Kuroda, Keita Abe, Souichi Segawa, Jian-Guo Wen, Hiromi Unoki, and Naoki Koshizuka, "Field-Induced Pinning Effect Depending on the Composition of Nd1+xBa2-xCu3O7-d Single Crystals Grown by the TSFZ Method." Superconductivity Research Laboratory, International Superconductivity Technology Center (ISTEC), 10-13 Shinonome 1-chome, Koto-ku, Tokyo 135, JAPAN; telephone +81 3 3536-5707; telefax +81 3 3536-5714; e-mail k-kuroda@mmc.co.jp. Key words: NdBa2Cu3O7-d, single crystal, traveling-solvent floating zone, flux pinning, peak effect. 74.25.Ha; 74.60.Ge; 74.60.Jg; 74.72.Jt.

D. D. Lawrie, J. P. Franck, J. R. Beamish, E. B. Molz, Wei-min Chen, and M. J. Graf, "Doping Dependence of the Critical Field H_[c2] and the Transition Temperature in Zn Doped YBa2(Cu1-xZnx)3O7-d." Presented at the Int. Conf. on Phys. and Chem. of Molecular and Oxide Supercond. (MOS'96), Karlsruhe, Germany, Aug. 2-6, 1996; to be published in J. Low Temp. Phys. Department of Physics, University of Alberta, Edmonton, Alberta, CANADA T6G 2J1. 74.72.Bk; 74.25.Fy; 74.25.Ha.

T. W. Li, R. J. Drost, P. H. Kes, C. Traeholt, H. W. Zandbergen, N. T. Hien, A. A. Monovsky, and J.J.M. Franse, "Enhanced Flux Pinning in Bi- 2212 Single Crystals by Planar Defects Introduced via Ti-Substitution." To be published in Physica C (in press). Contact R. J. Drost, Kamerlingh Onnes Laboratory, Leiden University, Nieuwsteeg 18, P.O. Box 9506, 2300 RA Leiden, THE NETHERLANDS; telefax +31 71 5275405; e-mail drost@rulgm0.leidenuniv.nl. Key words: critical current density, flux pinning, substitution effects, defect structure, single-crystal growth.

Y. P. Li, J. R. Liu, X. T. Cui, J. Z. Qu, Q. Y. Chen, and W. K. Chu, "Doping Silver into YBa2Cu3O7-d Films by 800 keV Ag+ Implantation at Room Temperature and Elevated Temperatures." Preprint #97:002; submitted to Appl. Phys. Lett. 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.

Guicun Ma, Yi Liu, and Xianxi Dai, "Resonant Tunneling Effect of Quantum Well-Superconductor Junction." To be published in Physica C (in press). Department of Physics, Fudan University, Shanghai 200433, PEOPLE'S REPUBLIC OF CHINA; telefax +86 21 6549 3232; e-mail xxdai@fudan.ihep.ac.cn. Key words: superconducting junction, quantum well, resonant tunneling. 74.80.Dm.

K.-H. Mueller, "ac Power Losses in Flexible Thick-Film Superconducting Tapes." Submitted to Phys. Rev. B. Division of Telecommunications and Industrial Physics, CSIRO, Lindfield, NSW 2070, AUSTRALIA; e-mail karl@dap.csiro.au. 85.25.Kx; 84.70.+p; 74.76.Bz; 74.25.Fy.

K.-H. Mueller and C. Andrikidis, "Critical Currents in Silver-Sheathed Bi-2223 Superconducting Tapes." To be published in the Proc. of the Int. Symp. on Advances in Supercond.: New Materials, Critical Currents and Devices, (ASMCCD '96), Mumbai, India, Sept. 17-20, 1996. Division of Telecommunications and Industrial Physics, CSIRO, Lindfield, NSW 2070, AUSTRALIA; e-mail karl@dap.csiro.au.

K.-H. Mueller, C. Andrikidis, and Y. C. Guo, "Irreversible Critical Current and the Anomalous Magnetic Moment Peak in Silver-Sheathed Pb-Bi- Sr-Ca-Cu-O Tapes." To be published in Phys. Rev. B. Division of Telecommunications and Industrial Physics, CSIRO, Lindfield, NSW 2070, AUSTRALIA; e-mail karl@dap.csiro.au. 74.60.Jg; 85.25.Kx; 74.80.Bj; 74.72.Hs.

K.-H. Mueller, C. Andrikidis, H. K. Liu, and S. X. Dou, "Intergranular and Intragranular Critical Currents in Bi-2223 Superconducting Tapes." To be published in the Proc. of the 8th Int. Workshop on Critical Currents in Supercond. (8th IWCC), Kitakyushu, Japan, May 27-29, 1996. Division of Telecommunications and Industrial Physics, CSIRO, Lindfield, NSW 2070, AUSTRALIA; e-mail karl@dap.csiro.au.

K.-H. Mueller, C. Andrikidis, H. K. Liu, and S. X. Dou, "Irreversible Intergranular Critical Current in Bi-2223 Superconducting Tapes." To be published in the Proc. of the 8th Int. Workshop on Critical Currents in Supercond. (8th IWCC), Kitakyushu, Japan, May 27-29, 1996. Division of Telecommunications and Industrial Physics, CSIRO, Lindfield, NSW 2070, AUSTRALIA; e-mail karl@dap.csiro.au.

K.-H. Mueller and K. E. Leslie, "Self-Field ac Loss of Bi-2223 Superconducting Tapes." Presented at the Appl. Supercond. Conf., Pittsburgh, PA, Aug. 25-30, 1996; to be published in IEEE Trans. Appl. Supercond. Division of Telecommunications and Industrial Physics, CSIRO, Lindfield, NSW 2070, AUSTRALIA; e-mail karl@dap.csiro.au.

David R. Nelson and Ady Stern, "Polymer Winding Numbers and Quantum Mechanics." Lyman Laboratory of Physics, Harvard University, Cambridge, MA 02138.

C. J. Olson, C. Reichhardt, J. Groth, Stuart B. Field, and Franco Nori, "Plastic Flow, Voltage Bursts, and Vortex Avalanches in Superconductors." Department of Physics, University of Michigan, Ann Arbor, MI 48109-1120; telephone (313) 647-5552; telefax (313) 764-6843; e-mail colson@umich.edu; Web site http://www-personal.engin.umich.edu/~nori; preprint also available at cond-mat@xxx.lanl.gov (#9612078). 64.60.Ht; 74.60.Ge.

L. Ozyuzer, Z. Yusof, J. F. Zasadzinski, R. Mogilevsky, D. G. Hinks, and K. E. Gray, "Apparent d_[x^2-y^2] Symmetry in the Tunneling Density of States of TI2Ba2CuO6." Submitted to Phys. Rev. B. Contact Janice Coble, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439; telefax (708) 252-9595; e-mail janice_coble@qmgate.anl.gov.

Lou Ping, "Effect of Spin Fluctuations on the Carrier Thermal Conductivity of Polycrystalline YBa2Cu3O8." To be published in Physica C (in press). Department of Physics, Anqin Normal College, Anqin 246011, PEOPLE'S REPUBLIC OF CHINA. Key words: normal-state properties, thermal conductivity, spin fluctuations.

G. Plesch, F. Hanic, and M. Jergel, "Chemical Aspects of the Preparation of High-Tc Superconducting Tl-Ba-Ca-Cu-O Films by Deposition from Aerosol." To be published in Thermochimica Acta. Department of Inorganic Chemistry, Faculty of Natural Sciences, Comenius University, 842 15 Bratislava, SLOVAKIA; telephone +42 7 796-326 or -273; telefax +42 7 729 064; e-mail plesch@fns.uniba.sk. Key words: aerosol deposition from nitrate solutions, high-Tc superconductor Tl2Ba2CaCu2Ox films, thermogravimetry, powder x-ray diffraction.

J. Ranninger and J.-M. Robin, "The Spin Gap in the Context of the Boson- Fermion Model for High Tc Superconductivity." To be published in Physica C (in press). Centre de Recherches sur les Tres Basses Temperatures, associe a l'UJF, CNRS, BP 166, F-38042 Grenoble Cedex 9, FRANCE; telefax +33 476 88 1038; e-mail secret@labs.polycnrs.gre.fr. Key words: pseudo gap, magnetic susceptibility, neutron scattering. 74.72.-h; 74.25.-q; 75.40.Gb.

G. Ravikumar, T. V. Chandrasekhar Rao, P. K. Mishra, V. C. Sahni, Subir Saha, S. S. Banerjee, N. G. Patil, A. K. Gover, S. Ramakrishnan, S. Bhattacharya, E. Yamamoto, Y. Haga, M. Hedo, Y. Inada, and Y. Onuki, "Effect of Field Inhomogeneity on the Magnetization Measurements in the Peak Effect Region of CeRu2 Superconductor." Presented at the Int. Symp. on Advances in Supercond.: New Materials, Critical Currents and Devices, (ASMCCD '96), Mumbai, India, Sept. 17-20, 1996; submitted to Physica C. Technical Physics and Prototype Engineering Division, Bhabha Atomic Research Centre, Mumbai 400 085, INDIA.

Anjali B. Riise, T. H. Johansen, and H. Bratsberg, "Critical State Magnetization of Hard Type-II Superconductors with Rectangular and Cylindrical Cross Sections." To be published in J. Superconductivity. Department of Physics, University of Oslo, 0316 Oslo 3, NORWAY. Key words: magnetization, hysteresis, type-II superconductors, critical state, critical current density. 74.60.Ge; 74.90.+n.

A. I. Rykov, S. Tajima, and F. V. Kusmartsev, "High-Field Paramagnetic Effect in Large YBa2Cu3O7-d Crystals." 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; telephone +81 3 3536-0618 or -5703 through -5705; telefax +81 3 3536-5714 or -5717. 74.60.Ge; 74.25.Ha; 74.60.Jg; 74.62.Bf.

A. I. Rykov, S. Tajima, and F. V. Kusmartsev, "High-Field Paramagnetic Effect in Large YBa2Cu3O7-d Crystals." To be published in the Proc. of the 9th Int. Symp. on Supercond. (ISS'96), Sapporo, Hokkaido, Japan, Oct. 21-24, 1996. Superconductivity Research Laboratory, International Superconductivity Technology Center (ISTEC), 10-13 Shinonome 1-chome, Koto-ku, Tokyo 135, JAPAN; telephone +81 3 3536-0618 or -5703 through -5705; telefax +81 3 3536-5714 or -5717. Key words: YBa2Cu3O7-d single crystals, paramagnetic Messner effect, fishtail effect, orbital glass.

Sergei A. Sergeenkov, "Dipole-Dipole Interaction of Josephson Diamagnetic Moments." To be published in Phys. Lett. A. Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, 141980 Dubna, Moscow Region, RUSSIA; e-mail ssa@thsun1.jinr.dubna.su. 74.50.+r; 74.80.Bj.

M. M. Sung, S. H. Lee, S. M. Lee, D. Martin, S. S. Perry, and J. W. Rabalais, "Low Energy Ar+ Cleaning, Damage and Sputtering of InP{100} Surfaces." Preprint #96:170; submitted to the Proc. of the Ion Implant Technol. Conf., Austin, TX, June 17-21, 1996. 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.

Ichiro Takeuchi, "In-Plane Aligned a-Axis Oriented YBa2Cu3O7-x Heterostructures and Josephson Junctions." Submitted as a Doctor of Philosophy thesis (University of Maryland). Department of Physics, University of Maryland, College Park, MD 20742.

R. I. Tomov, V. P. Manolov, P. A. Atanasov, V. N. Tsaneva, D. G. Ouzounov, and V. I. Tsanev, "Experimental and Theoretical Investigation of Cumulative Laser Irradiation Effects in YBCO Thin Film Pulsed Laser Deposition." To be published in Physica C (in press). Institute of Electronics, Bulgarian Academy of Sciences, 72 Tzarigradsko Shose, Sofia, BULGARIA. Key words: superconductivity, thin films, laser ablation. 74.76.Bz; 81.15.Fg.

D. Vaknin, L. L. Miller, J. L. Zarestky, and D. C. Johnston, "Elastic and Quasielastic Neutron Scattering Study of the Spin-1/2 Square Lattice Antiferromagnet Sr2CuO2Cl2." To be published in Physica C (in press). Ames Laboratory-USDOE and Department of Physics, Iowa State University, Ames, IA 50011-3020; telephone (515) 294-6023; telefax (515) 294-0689; e-mail vaknin@ameslab.gov. 74.72.Jt; 75.25.+z; 75.50.Ee; 75.40.Cx.

N. Vandewalle, R. Cloots, and M. Ausloos, "Physico-Chemical Causes for the Microstructure of Melt-Textured YBa2Cu3O7-d/Y2BaCuO5 Composites." To be published in Supercond. Sci. & Technol. SUPRAS, Institute of Physics B5, University of Liege, B-4000 Liege, BELGIUM; telephone +32 4 366 3703; telefax +32 4 366 2990; e-mail vandewal@gw.unipc.ulg.ac.be; Web site http://www.phe.ulg.ac.be/micro/micro.html.

Valerii M. Vinokur, "Glassy Dynamics of Driven Elastic Manifolds." Presented at the Landscape Paradigms in Physics and Biology Conf., Los Alamos, NM, May 14-17, 1996; to be published in Physica D. Contact Janice Coble, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439; telefax (708) 252-9595; e-mail janice_coble@qmgate.anl.gov. Key words: elastic maniford, disorder, creep motion, glassy response, algebraic distributions.

V. K. Vlasko-Vlasov, U. Welp, G. W. Crabtree, V. V. Kabanov, and V. I. Nikitenko, "Meissner Holes and Turbulent Flux Structures in High-Tc Superconductors." To be presented at the 5th Int. Conf. on Materials and Mechanisms of Supercond. and High-Temp. Supercond. (M2S-HTSC V), Beijing, People's Republic of China, Feb. 28-March 4, 1997. Contact Janice Coble, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439; telefax (708) 252-9595; e-mail janice_coble@qmgate.anl.gov.

J. L. Wagner, O. Chmaissem, J. D. Jorgensen, D. G. Hinks, P. G. Radaelli, B. A. Hunter, and W. R. Jensen, "Multiple Defects in Overdoped Tl2Ba2CuO6+d: Effects on Structure and Superconductivity." Contact Janice Coble, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439; telefax (708) 252-9595; e-mail janice_coble@qmgate.anl.gov.

X. L. Wang, J. Horvat, H. K. Liu, J. N. Li, and S. X. Dou, "Anomalous Magnetization Peak Effect in Spiral-Grown Bi2Sr2CaCu2Oy Crystals." To be published in Phys. Rev. B (in press). Centre for Superconducting and Electronic Materials, University of Wollongong, Wollongong, NSW 2522, AUSTRALIA; telefax +61 42 213112; e-mail xlw01@uow.edu.au. 74.60.Ge; 74.72.Hs; 81.10.Aj.

X.-J. Wu, A. Tokiwa-Yamamoto, T. Tatsuki, S. Adachi, and K. Tanabe, "Transmission Electron Microscopy Study of New Intergrowth Phases in Hg- Tl-Ba-Ca-Cu-O Compounds." To be published in Physica C. Superconductivity Research Laboratory, International Superconductivity Technology Center (ISTEC), 10-13 Shinonome 1-chome, Koto-ku, Tokyo 135, JAPAN; telephone +81 3 3536-5703 through -5705; telefax +81 3 3536-5714 or -5717.

M. Yeadon, P. J. Hirst, K. R. Locherer, J. Chrosch, J. S. Abell, M. Aindow, F. Wellhofer, and E.K.H. Salje, "The Effects of Al Substitution on the Microstructure and Properties of Laser-Ablated Epitaxial YBa2Cu3O7-d Films on (001) MgO." To be published in Physica C (in press). Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801; telefax (217) 244-2278; e-mail yeadon@uimr17.mrl.uiuc.edu. Key words: thin films, structural phase transition, aluminum doping, scanning tunneling microscopy, transmission electron microscopy, x-ray diffraction.

X. F. Zhang, G. Van Tendeloo, D. W. Hu, and V.A.M. Brabers, "Room Temperature (2a x 2b) Superstructure Formed in Sr-Substituted Bi2(Sr1.6Y0.4)CaCu2Oy Single Crystals." Submitted to Physica C. Materials Science Division, Bldg. 223, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439; telephone (630) 252-4764; telefax (630) 252-7777; e-mail xiaofeng_zhang@qmgate.anl.gov. Key words: Bi- Sr-Y-Ca-Cu-O, microstructure, transmission electron microscopy. 61.16.Bg; 61.50.Em; 74.72.Hs.

*Feb. 6 - 7, 1997: The DOE 1997 Wire Development Workshop, Marriott/Bay Point in Panama City, Florida. Objectives are to hear reports on research progress, trends, and problems in HTS coated conductor and powder-in-tube wire; review critical program needs and develop strategies for addressing issues in BSCCO wire and its applications, YBCO coated conductors, and low ac loss conductors; and interact with colleagues to further strengthen collaborative efforts in the program. Plenary sessions followed by working groups that address issues in that topical area. For more information, contact Jim Daley, Department of Energy, telephone (202) 586-1165; Chris Platt, Department of Energy, telephone (202) 586-8943; or Craig Matzdorf, Energetics, telephone (410) 290-0370.

Feb. 20 - 21, 1997: International Workshop: Frontiers of High-Tc Superconductors -- Coherence, Josephson Plasma, and Exotic Materials, Tsukuba Center for Institutes, STA, Tsukuba, Japan. Aim is to put forward new experimental and theoretical results of tunneling phenomena, Josephson plasma, vortex states, physical properties of high-Tc superconductors, and new types of materials including spin-ladder structures. Invited oral presentations and contributed poster papers. Proceedings to be published in J. Supercond. Official language is English. For information contact K. Kadowaki, University of Tsukuba, 1- 1-1 Tennoudai, Tsukuba City, Ibaraki 305, Japan; telephone +81 298-53- 5291; telefax +81 298-55-7440; e-mail kadowaki@ims.tsukuba.ac.jp.

*Feb. 28 - March 4, 1997: Fifth International Conference on Materials and Mechanisms of Superconductivity and High-Temperature Superconductors (M2S-HTSC-V), Beijing, China. Two plenary sessions, 30-33 microsymposia and oral sessions (three or four parallel sessions, at least two sessions to be reserved for latest new results and outstanding post deadline contributions), three tutorial sessions, and poster sessions. Topics include high-Tc materials; physical properties of high-Tc materials; magnetism and superconductivity; vortices, pinning, and flux melting; thin films and multilayers; Josephson junctions; applications; heavy fermions; organic superconductors; fullerenes; and theory. Exhibition of high-Tc superconducting materials, low-temperature experimental appliances, and cryogenic engineering and refrigeration instruments. Conference language is English. For information, contact D. Jin, M2S-HTSC-V Secretariat, Cryogenic Laboratory, Chinese Academy of Sciences, P.O. Box 2711, Beijing 100 080, People's Republic of China; telephone +86 10 6 255 1143; telefax +86 10 6 256 4049; e-mail djin@cl.cryo.ac.cn; Web site http://sun1.bham.ac.uk/hey/conferences/.

*April 3 - 4, 1997: Workshop on ac Losses, San Francisco Marriott, San Francisco, CA. Sponsored by the Electric Power Research Institute (EPRI). Two-day workshop will cover theoretical and experimental research on power-line-frequency (50-60 Hz) ac losses in high- temperature superconductors, and the influence such losses have on the design of HTS devices for electric power applications. Program will consist of talks, posters, and workshop discussions. No registration fee, but attendance will be limited to 50 participants. Workshop will follow Symposium R: Materials Issues Related to Development of Textured High-Temperature Superconducting Conductors at the 1997 MRS Spring Meeting, being held April 1-2, 1997, at the same location. Applications via e-mail consisting of name, institution, address, phone and fax numbers, e-mail address, and an abstract, will be used to select oral and poster presentations. Application deadline, February 1, 1997. For further information, contact the workshop organizers, preferably by e- mail: John R. Clem, A517 Physics, Iowa State University, Ames, IA 50011, telephone (515) 294-4223, telefax (515) 294-0689, e-mail clem@ameslab.gov; or Masaki Suenaga, Brookhaven National Laboratory, Bldg. 480, Upton, NY 11973, telephone (516) 282-3518, telefax (516) 282- 4071, e-mail mas@sun2.bnl.gov. For separate information about the 1997 MRS Spring Meeting and accommodations, contact the Materials Research Society, 9800 McKnight Road, Pittsburgh, PA 15237-6006, telephone (412) 367-3003, telefax (412) 367-4373, e-mail info@mrs.org.

*April 7 - 9, 1997: Fourth HTS Workshop on High Frequency Applications of Thin Films, Fabrication, Passive and Active Devices, Oxford, United Kingdom. Follows previous three successful HTS Workshops held at the University of Twente in 1994, 1995, and 1996. Five sessions comprising the Workshop will cover: 1) deposition of thin films; 2) microwave properties; 3) the design, fabrication, and performance of passive microwave devices; 4) the fabrication of Josephson junctions; and 5) the applications of HTS Josephson devices. Oral and poster contributions are solicited; proceedings to be published. Abstract deadline, March 1, 1997; registration deadline March 21, 1997. Further details available from D. Dew-Hughes, A. P. Jenkins, or C.R.M. Grovenor, Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, United Kingdom; telefax +44 1865 273010 or -273764; e-mail grovenor@materials.oxford.ac.uk; Web site http://www.materials.ox.ac.uk/Materials/Conferences/hts4thinfilms.html. Registration can also be carried out via the Web page.

April 22 - 25, 1997: Specialized Colloque AMPERE/RAMIS'97: XVII Conference on Radio and Microwave Spectroscopy, Poznaq, Poland. To cover recent developments in graphite and fullerene research as well as the application of magnetic resonance methods in localized and conducting electrons studies, ferroelectrics, molecular crystals, high- temperature superconductors, paramagnetic complexes, and others. Abstract deadline, February 28, 1997. Papers to be published. For further information, contact Lidia Piekara-Sady, Institute of Molecular Physics, Smoluchowskiego 17, PL-60179 Poznaq, Poland; telefax +48 61 684524, e-mail lpiekara@ifmpan.poznan.pl.

*June 26 - 28, 1997: Sixth International Superconductive Electronics Conference (ISEC'97), Intercontinental Hotel, Berlin, Germany. Conference will encompass all aspects of superconductive electronics including the enabling technologies, devices, circuits, instrumentation, theory, and applications ranging from very-low-frequency SQUIDs to ultra-high-speed digital circuits. Of special interest will be the progress towards commercial products. Oral and poster sessions with no parallel sessions. Topics will include: physics of superconductive devices, superconducting device fabrication, process technology, superconductive digital and analog circuits and devices, new devices such as superconductive transistors and power devices, applications and instrumentation, and others. For further information, contact ISEC'97 Conference Secretariat, Dipl. Phys. Silvia Knappe, Physikalisch- Technische Bundesanstalt, Abbestr. 10-12, D-10587 Berlin, Germany; telefax +49 30 3481-490; e-mail isec97@ptb.de; Web site http://www.lab1033.berlin.ptb.de/10/102/isec97/start.htm.

July 7 - 9, 1997: International Workshop on the Processing and Applications of Superconducting (RE)BCO Large Grain Materials, Fitzwilliam College, University of Cambridge, United Kingdom. Topics will include (1) Growth Process: growth mechanisms and morphology, seeding effects, and faceting; (2) Processing: process optimization, rate of production, control of growth morphology, oxygenation, irradiation, hot pressing, joining, and machining; (3) Microstructural Properties: homogeneity, 211 distribution, platelet boundaries, dislocations, second-phase segregation, and radiation damage; (4) Superconducting Properties: Jc-microstructure correlation, role of defects, factors limiting Jc, and trapped field; (5) Applications: materials requirements, device design, and demonstrators development. Abstract deadline, March 20, 1997. For further information and submission of abstracts contact Wai Lo, Workshop Secretariat, PASREG, IRC in Superconductivity, University of Cambridge, Madingley Road, Cambridge CB3 0HE, United Kingdom; telefax +44-1223-337074; e-mail wl103@hermes.cam.ac.uk; Web site http://www.sucon.cam.ac.uk/Workshops/PASREG.html.

July 19 - 27, 1997: 3rd International Summer School On High Temperature Superconductivity, Eger, Hungary. Objective is to provide overview of basic and up-to-date information on the theories and newest results in fundamental research and applications of high-temperature superconductors. Last days of the School to be devoted to a scientific conference (poster sessions and 15-minute oral presentations) for participants to present results of their own scientific work. Will contain oral lectures and presentations including the following topics: second decade of high-Tc superconductivity, new theories, physical properties, characterization and measurements of physical properties, new trends in preparation techniques, crystal structures, physical properties and morphology, manufacturing, and small and large-scale applications. Abstract deadline, March 1, 1997. Proceedings to be published; tutorial lectures will be published as a textbook, "Textbook of the Summer School." Official language is English. For further information contact Istvan Vajda, Department of Electrical Machines and Drives, Technical University of Budapest, Egry Jozsef utca 18, H-1111 Budapest, Hungary; telephone +36 1 463-2961or -3600; e-mail vajda@ntb.bme.hu; Web site http://docs4.mht.bme.hu/~farkas.

Nov. 16 - 21, 1997: ASME International Mechanical Engineering Congress & Exposition: Technical Session on Low-Temperature Electronics, Dallas, Texas. Session jointly organized by the Heat Transfer Division, the Superconductivity Technical Committee, and the Electronic Packaging Division will focus on thermal and mechanical aspects of superconducting and semiconducting electronics. Potential topics include thermal management, thermal stresses, microscale effects, heat transfer at cryogenic temperatures, and thermal and mechanical properties at low temperatures. Contact Patrick E. Phelan, Arizona State University, Department of Mechanical & Aerospace Engineering, P.O. Box 876106, Tempe, AZ 85287-6106; telephone (602) 965-1625; telefax (602) 965-1384; e-mail phelan@asu.edu.

April 20 - 25, 1998: The Seventh Conference on Frontiers of Electron Microscopy in Materials Science, Kloster Irsee, Irsee, Germany. Purpose of this meeting is to establish the current state of the art of quantification of all relevant techniques used in electron microscopy including XEDS, EELS, Z-contrast, HREM, conventional TEM, CBED, and in- situ. Topical area: quantitative methods in electron microscopy. Number of participants limited to 100 (30 invited speakers, 20 invited session chairs, and 50 participants). For information, contact Kloster Irsee, Schwaebisches Tagungs- und Bildungszentrum, Klosterring 4, 87660 Irsee, Germany; telephone +49 8341 906-00; telefax +49 8341 742-78. ________________________________________________________________________

RESOURCES

Information

Proceedings: Critical Currents in Superconductors: Proceedings of the 8th International Workshop, Kitakyushu, Japan (May 27-29, 1996), edited by Teruo Matsushita and Kaoru Yamafuji. Contains 18 invited and 96 contributed papers that cover the properties of flux lines and their phase diagrams; the irreversibility line and the electromagnetic phenomena associated with flux dynamics; flux-pinning properties; and critical-current characteristics in bulk materials, tapes, and thin films. Contact World Scientific Publishing Co. Inc., 1060 Main St., River Edge, NJ 07661; telephone (800) 227-7562 or (201) 487-9655; telefax (201) 487-9656. In Europe, World Scientific Publishing Co. Ltd., 57 Shelton Street, Covent Garden, London WC2 9HE, UK; telephone +44 171 836 0888; telefax +44 171 836 2020. In Asia, World Scientific Publishing Co. Pte. Ltd., Farrer Road, P.O. Box 128, Singapore 9128; telephone +65 3825663; telefax +65 3825919. Information also available at the Web sites http://www.singnet.com.sg/~wspclib or http://www.wspc.co.uk.

Proceedings: Applications of Synchrotron Radiation Techniques to Materials Science III, MRS Symposium Proceedings Series, Vol. 437, edited by L. Terminello, S. Mini, D. L. Perry, and H. Ade. Focuses on the various types of information that can be obtained from synchrotron- related techniques in order to expand the use of this powerful experimental approach to materials research. Topics include structure of reduced dimensional materials, microscopy, topography and tomography, x-ray probes of solids, and materials characterization with x-ray probes. Publ. 1996; price $66 (members), $76 (US list), $88 (non-US list); ISBN 1-55899-340-1. Contact the Materials Research Society, Customer Services Dept., 9800 McKnight Road, Pittsburgh, PA 15237-6006; telephone (412) 367-3012; telefax (412) 367-4373; e-mail info@mrs.org.

Book: Chemical Equilibria Bases for Oxide and Organic Superconductors, by R. J. Thorn (Argonne). Discusses recognition of the role of chemical equilibria in a fundamental manner and contains quantitative analyses and interpretations of the pertinent data and interrelations among the three signatures of superconductivity -- resistance, diamagnetic susceptibility, and specific heat. Topics include: crystal structures, chemical potential of oxygen, electronic structures, electrical conductivity, chemical equilibrium in the transition to the paired diamagnetic state, interrelations among the three signatures, and index. Publ. 1996; 200 pp.; price $69.95; ISBN 3 0-471-10363-2. Contact John Wiley & Sons, Inc., Distribution Center, 1 Wiley Drive, Somerset, NJ 08875-1272; telephone (908) 469-4400; telefax (908) 302- 2300.

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. 11, #3, February 1, 1997.