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, NSF, 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:

Bi Cuprates

The in-plane and out-of-plane resistivities rho_a(T) and rho_c(T) have been measured by T. Watanabe (NTT) et al. in Bi2Sr2CaCu2O8+d (Bi-2212) single crystals with precisely controlled oxygen contents. In the underdoped region, a deviation from T-linear in-plane resistivity, which evidences the opening of the spin gap, was observed, while the out-of- plane resistivity could be described by the formula rho_c(T) = (a/T)exp(Delta/T) + c. In contrast to the YBa2Cu3O7-d system, in Bi- 2212 the onset of semiconducting behavior in rho_c(T) does not coincide with the opening of the spin gap seen in rho_a(T).

Measurements of the ac transport current losses of nine different Bi- 2223 tapes with varying filament geometries have been carried out by H. Eckelmann et al. (Karlsruhe) using frequencies in the range 13-770 Hz at 77 K. The tapes had Ag, AgMg, or AgAu sheaths, and included those with novel geometries [multifilamentary wire-in-tube (WIT) and jelly-roll] and different twist pitches. The ac losses were found to lie within the Norris limits for rectangles and ellipses except for the jelly-roll and AgAu tapes, which had lower losses.

A preprint by M. Daeumling (Karlsruhe) reports numerical calculations of the hysteresis losses in superconducting tapes subjected to a perpendicular ac field of amplitude H. For strips with width-to- thickness ratios much larger than 100, the losses vary as P proportional to H^n, where n = 4, as expected theoretically for a 2D thin strip. For tapes with aspect ratios of 20-30, typical of those of Bi-2223 tapes, however, the author finds an exponent of n ~~ 3.5.

Measurements of the ac transport current losses of Ag-sheathed 19- filament (Bi-Pb)-2223 twisted and untwisted tapes are reported by T. Fukunaga (Gifu) and A. Oota (Toyohashi). The authors report that the filament twist neither causes a notable influence on the loss behavior nor equalizes the current distribution in the filaments and that the main contribution to the losses comes from hysteresis losses.

A paper by K. Kwasnitza (PSI-Villigen) et al. reports that in twisted multifilament Bi-2223/Ag tapes the introduction of BaZrO3 barriers around the filaments increases the transverse matrix resistivity at 77 K by a factor of 10 and shifts the coupling loss maximum in transverse alternating magnetic fields from 4.5 Hz to about 45 Hz. For 50 Hz applications the twist length should be further reduced and the barrier thickness increased.

The current-voltage (I-V) characteristics of long Bi-2223/Ag multifilamentary tapes with different bending strains have been measured by M. K. Al-Mosawi (Southampton) et al. over a large range of electric fields (10^[-12]-10^[-3] V/cm). The experimental data are interpreted in terms of current-induced unbinding of thermally created vortex- antivortex pairs. The authors explain the shape of the I-V curves via the appearance of microcracks during the bending process, which cause the superconducting intergrain contacts to have different critical currents.

Using a scanning Hall sensor with an active area 50 micrometers x 50 micrometers, A. Oota (Toyohashi) et al. have measured the self-field distribution at 77 K due to dc transport currents in Ag-sheathed (Bi- Pb)-2223 monofilamentary and multifilamentary tapes. The field distribution for both cases is close to that expected from the Bean model for a solid superconductor with elliptical cross section, in which the current flows with density Jc, -Jc, or 0 in the superconductor, and the boundaries of the current distribution form concentric ellipses with the same aspect ratio as the sample's.

Progress in the development of HTS tapes and multistrand conductors for power transmission cables is reported by M. Leghissa (Siemens-Erlangen) et al. Using a total of 2 km of (Bi,Pb)-2223 tape, the authors fabricated a flexible 10.5 m, four-layer, 145-tape machine-stranded cable conductor in a design with individual layers insulated from each other. A special low-loss design that equalizes the current in each layer was employed. The authors report 55 Hz ac transport current losses of 0.9 W/m at 2,000 A_[rms] and 77 K. The tapes have reproducible Jc in the 20 kA/cm^2 range over long lengths (>100 m) and up to 41 kA/cm^2 over short lengths.

RBa2Cu3O7-d

The vortex-state Hall conductivity sigma_[xy] of YBa2Cu3O7-d single crystals has been measured by D. A. Beam et al. (Caltech) and found to be independent of the density and orientation of correlated disorder. The authors observed a universal sigma_[xy] for a given reduced temperature T/Tc, magnetic-field strength H, and magnetic-field orientation theta relative to the crystalline c axis in five samples of different controlled defects. The transport scattering times tau, derived from the data using the model of Feigel'man, are consistent in magnitude with those derived from other measurements of the quasiparticle scattering time.

Melt-textured samples of NdBa2Cu3O7-d (Nd-123) with different amounts of Nd4Ba2Cu2Oy (Nd-422) additions have been investigated by A. M. Hu et al. (Beijing). The magnetic levitation force was found to be optimized for the composition NdBa2Cu3O7-d + 0.4 Nd4Ba2Cu2Oy. The authors show that microcracks in the bulk NdBa2Cu3O7-d are reduced by the presence of Nd4Ba2Cu2Oy particles, and they attribute the enhancement of the magnetic levitation force to the suppression of weak links in grains.

An analysis of microcracking in melt-processed RBa2Cu3O7-d (123) superconductors is presented in a preprint by P. Diko (Kosice). The author calculates the microstresses introduced in the 123 matrix by the different thermal expansivities and elastic constants of the 123 matrix and the 211 (or 422) inclusions. He also calculates the criterion for ab microcracking [cracks normal to the c direction initiated at the 211 (422) particle] and finds the critical Nd-422 particle radius, below which ab microcracking does not occur, to be 0.24 micrometers, in good agreement with the experimental value.

The flux-creep behavior of a melt-textured sample of YBa2Cu3O7-d showing a fishtail effect (maximum in Jc at finite B) has been investigated by M. Reissner and J. Lorenz (Vienna) using several different methods. The authors find that the pinning centers that dominate in the field and temperature regime where the fishtail occurs have higher activation energies and show a two-dimensional pinning behavior with a change from single vortex creep to collective vortex creep with increasing field and temperature. These pinning centers are strongly influenced by the oxygen content.

Other Cuprates

As reported by N. L. Wu (TCSUH) et al., a new family of C-free high- temperature superconducting oxides in the Ba-Ca-Cu-O system with Tc up to 107 K has been synthesized under high pressure. Structural analyses, based on x-ray and electron diffraction and high-resolution electron microscopy, have revealed that these oxides can be represented as CaBa2Ca2Cu3O9-d (Ca-1223-Ba) and that they are isostructural with Tl- 1223-Ba. The new oxides have the same active block of [(CuO2)(Ca)(CuO2)(Ca)(CuO2)] found in other high-temperature superconductors, but they permit cation mixing and substitution of Ca by Cu within the charge-reservoir block [(BaO)(CaO)(BaO)]. Such variations are responsible for corresponding variations in composition and superstructure, but they have only a minor influence on Tc.

New nonsuperconducting phases of general formula Hg2Ba2LnCu2O8-d with Ln = Nd-Gd, Dy-Lu have been synthesized by S. M. Loureiro (CNRS-Grenoble) et al. using a high-pressure, high-temperature technique. At temperatures between 25 K and 28 K, the susceptibility of the Sm, Eu, Dy, and Ho samples exhibits a sharp cusp, attributed to antiferromagnetic ordering of the Cu spins.

Measurements of the temperature dependence (20-300 K) of the resistivity, thermopower, and thermal conductivity of polycrystalline Hg-1223 with nominal composition Hg1.4Ba2Ca2Cu3O8+d are reported by H. Bougrine (Liege) et al. The authors also focus attention on the fluctuation contributions to these transport properties.

Vortices

The critical current density Jc in vicinal YBa2Cu3O7-d films has been measured by P. Berghuis et al. (Cambridge) as a function of the orientation of the magnetic field. When both the field and the Lorentz force were oriented parallel to the ab plane, the authors observed a minimum in Jc. The temperature dependence and angular range of the minimum suggest that this Jc anomaly is related to the development of a kinked vortex state consisting of pancake vortex segments and string segments. The Jc minimum reveals that the pinning force for vortex strings is weak in the presence of a Lorentz force along the ab plane as a consequence of the intrinsic nature of the vortex strings. This is in sharp contrast to the strong intrinsic pinning of vortex strings which occurs when the Lorentz force is perpendicular to the ab planes.

Scanning tunneling microscopy has been used to probe the local density of (bound) states (LDOS) near the vortex core. As shown theoretically in a preprint by N. Hayashi et al. (Okayama), energy-gap anisotropy has a strong influence upon the spatial dependence of the LDOS. The authors show, for example, that the observed characteristic structure of the LDOS in the layered hexagonal superconductor 2H-NbSe2 can be well reproduced by assuming an anisotropic s-wave gap in the hexagonal plane. To understand the rich electronic structure observed in the STM experiments, the authors note that it is useful to interpret the LDOS in terms of quasiparticle trajectories. The authors also point out new features in the LDOS that should be resolvable at lower temperatures in samples of higher purity.

Measurements of the voltage-noise power spectrum of a Bi2Sr2CaCu2O8+d (Bi-2212) single crystal in the vicinity of the vortex-lattice melting transition are reported by Y. Zhao (New South Wales) et al. As melting proceeds, the authors find that the vortex motion (a) is highly correlated at the early stages, (b) changes into an extended dissipative motion with self-organized criticality, and (c) finally becomes completely random.

The first penetration of magnetic flux (vortices) into a type-II superconducting disk of finite thickness in a transverse magnetic field has been theoretically analyzed by A. V. Kuznetsov (Moscow State) et al. The authors account for anisotropy, bulk pinning, and the geometrical barrier in considering penetration into a superconductor of rectangular cross section. The authors find that flux pinning at the edge corners influences the penetration field.

A preprint by M. Benkraouda and J. R. Clem (Ames Lab-Iowa State) considers a flat type-II superconducting strip in a perpendicular magnetic field H_a and calculates the magnetic-field-dependent critical current I_c(H_a) due solely to the geometrical barrier. At the critical current (for H_a not too small), there is a vortex-filled region on one side of the strip and a vortex-free region on the other side.

Theory

The magnetization of small superconducting particles has been calculated by P. Singha Deo (Antwerp) et al. using the Ginzburg-Landau and Maxwell equations. The authors find results in general agreement with the magnetization jumps and oscillations found in the experiments of A. K. Geim et al. [Superlatt. Microstruct. 21 (1997)].

The power absorbed by the Josephson plasma in high-Tc cuprates with finite dimensions has been calculated by S. Takahashi (Tohoku) et al. for a microwave field H_[ac] applied parallel to the ab plane. This field induces a screening current perpendicular to the ab planes at the ends of a sample of length L and excites the transverse Josephson plasma. The calculated microwave absorption spectrum is predicted to exhibit peaks depending upon L due to the interference of the Josephson plasma waves. Good agreement is found with recent experiments on Bi- 2212 crystals.

The transmission of obliquely incident p-polarized electromagnetic waves through an anisotropic superconducting slab immersed in a dielectric medium has been calculated by G. Hollauer (Rio de Janeiro) and M. M. Doria (Fluminense) for a sample whose c axis is perpendicular to the surface. Above the plasma frequency, the superconductor is a natural optical resonator, and the minimum of the transmission peaks is modulated by an envelope function associated with the Brewster condition.

The quasiparticle reflection and transmission properties at normal conductor-superconductor interfaces are discussed by C. Honerkamp and M. Sigrist (ETH-Zurich) for unitary and nonunitary spin-triplet pairing states recently proposed for Sr2RuO4. The authors find resonance peaks in the Andreev reflection amplitude, which are related to surface bound states in the superconductor. The authors propose a possible experiment to distinguish between unitary and nonunitary states.

A preprint by A. I. Posazhennikova and M. V. Sadovskii (Ekaterinburg) reports a Ginzburg-Landau calculation of the slope of the upper critical field dH_[c2]/dT near Tc in s- and d-wave superconductors as a function of anisotropic normal impurity scattering. For d-wave pairing, the authors find that the slope has a nonlinear dependence on disorder.

The density of states N(omega) of a dirty but homogeneous superconductor in a high magnetic field has been calculated by S. Dukan (Goucher) and Z. Tesanovic (Johns Hopkins). The authors calculate how N(omega) behaves as one crosses from weak scattering to the strong scattering limit. They find that when the disorder becomes stronger than a critical value, a finite density of states occurs at the Fermi surface.

The relative character of the planar p_[x,y] and axial p_z hole states in the pp-pi band in Y1-xPrxBa2Cu3O7-d has been calculated as a function of hole count by I. I. Mazin (NRL and George Mason) and A. I. Liechtenstein (Julich) using the localized model of Fehrenbacher and Rice and the band model of Liechtenstein and Mazin. The experiments of M. Mertz et al. [Phys. Rev. B 55, 9160 (1997)] fall between the two theoretical predictions.

The infinite-U three-band Hubbard model has been considered in a preprint by F. Becca et al. (Roma) to describe the CuO2 planes of the high-temperature superconducting cuprates. The authors investigate charge instabilities when the model is extended with a nearest-neighbor repulsion between holes on Cu d and O p orbitals and in the presence of a long-range Coulomb repulsion. An effective singular attraction arises in the proximity of the charge-density-wave instability, yielding both a strong pairing mechanism and anomalous normal-state properties.

The validity of the two-dimensional t-t'-U model as a minimal model for the cuprate superconductors is questioned in a preprint by A. Avella (Salerno) et al. The authors find that it is impossible to find a reasonable set of parameters for YBa2Cu3O7-d that can reproduce the position of the Van Hove singularity as predicted by ARPES experiments.

Formulas for the temperature dependence of 3D paraconductivity near the superconducting transition have been derived by P. Konsin (Tartu) et al. using the Kubo formalism and the linearized Ginzburg-Landau equations for a two-band model with interband scattering of pairs. The authors find that the Aslamasov-Larkin formulas are modified in this model.

A preprint by A. Bill (LBL) et al. presents a detailed study of the influence of nonadiabaticity and magnetic impurities on the value of the isotope coefficient. The authors show that both effects must be taken into account to describe the oxygen isotope effect in Pr-doped and oxygen-depleted YBa2Cu3O7-d.

A calculation of the superconducting order parameter accounting for (a) the long-range and short-range parts of the electron-lattice interaction and (b) the Coulomb repulsion between charge carriers has been carried out by A. Bill (LBL) et al. The authors find that whereas the long- range electron-lattice coupling determines the anisotropy of the order parameter, the Coulomb repulsion and short-range interactions determine its symmetry. Thus, different high-Tc superconductors may have s-wave or d-wave symmetry, depending upon the relative strength of the interactions involved in the pairing.

Thin Films

A method to planarize the surface of a YBCO film down to a standard deviation of 1 nm or better has been developed by W. K. Chu (TCSUH) et al. The method involves smoothing the surface by ion-cluster-beam (ICB) bombardment (around 3,000 Ar atoms per cluster), followed by annealing in oxygen ambient to regrow the damaged surface layer. Additional YBCO layers can be grown epitaxially on the treated surface, indicating that this method is adequate for multilayer thin-film processing.

A preprint by C. Prouteau (Caen) et al. reports that using La4- xBaxCu5O13-d as a template layer induces a-axis growth of YBa2Cu3O7-d films, although the presence of c-axis domains at the interface is not entirely suppressed. The authors also have demonstrated that La4- xBaxCu5O13-d can be used as an intermediate layer for SNS structures permitting the growth of a second YBCO layer with a-axis orientation.

A hot-wall metal-organic chemical-vapor-deposition (MOCVD) apparatus has been developed by Y. Ito (SRL-ISTEC) et al. for the deposition of YBa2Cu3O7-d films on arbitrarily shaped substrates using liquid-metal organic sources. The authors report the deposition of YBCO films on both sides of a LaAlO3 (100) substrate, with both films showing nearly the same superconducting properties. The authors also report the deposition of a biaxially aligned YBCO film on a (100) facet of a single-crystalline SrTiO3 fiber; the YBCO film was subsequently thickened by the liquid-phase-epitaxy (LPE) method.

Measurements of the linear dynamic conductivity sigma(f) = sigma' - i[sigma"] parallel to the CuO2 planes of superconducting YBa2Cu3O7-d films are reported by I. Wilke (Hamburg) et al. for frequencies f = 1kHz - 2 THz and temperatures 10-96 K. A crossover in the behavior of sigma(f,Tc) as a function of frequency is described in terms of the competition between the Drude contribution and critical fluctuations.

As reported by W. Markowitsch (Wien) et al., thin films of oxygen- depleted YBa2Cu3Ox (x ~~ 6.6) were prepared by pulsed-laser deposition on SrTiO3 substrates cut with tilt angles of 10 degrees and 20 degrees relative to the [001] direction, resulting in a step-like growth of the layers. The resistance showed semiconducting behavior along the projection of the c axis to the film surface and metallic behavior along the perpendicular direction, indicating that the former is dominated by the c-axis resistivity and the latter by the ab-plane resistivity of YBa2Cu3Ox. Long-term illumination of the samples with a 100 W halogen lamp resulted in a significant conductivity enhancement in both directions.

Hg-1223 films deposited using a two-step spray/press process on a flexible Ni substrate coated with Cr(Ag,Pd) have been found by R. L. Meng et al. (TCSUH) to have self-field Jc ~~ 7 x 10^4 A/cm^2 at 77 K.

A finite-element, coupled heat-transfer and thermal-stress analysis has been developed by B. Gu (Arizona State) et al. for a thin-film high-Tc device. The authors calculate the peeling stress (the normal stress at the film/substrate interface) and the peeling stress intensity factor for different substrate materials, YBCO film lattice-direction combinations, and current densities.

Junctions

The effects of disorder on the in-plane density of states of YBa2Cu3O7-d have been investigated by M. Aprili (Illinois-Urbana) using planar tunneling spectroscopy. The authors find that low-fluence 1 MeV He^+ irradiation reduces the YBa2Cu3O7-d Tc and mean free path without altering the junction quality. As the dirty limit is approached, the zero-bias conductance peak (ZBCP) disappears, as expected for a quasiparticle Andreev bound state. The authors attribute the broadening of the ZBCP to a damage-induced increase in the quasiparticle scattering rate. This rate is a direct measure of the pair-breaking strength and accounts for the Tc suppression.

Two preprints by A. Odagawa et al. (Matsushita Electric) and M. Sakai et al. (Matsushita Electric) report on properties of stacked intrinsic Josephson tunnel junctions in (Bi,Pb)2Sr2Ca2Cu3O10+d [(Bi,Pb)-2223] thin films. The first paper presents I-V characteristics along the c-axis showing a six-branch structure corresponding to the six tunnel junctions and edge structure representing the superconducting gap. The second paper reports observations of phase-locked switching with current-biased measurements and branching structures with voltage-biased measurements.

Applications

Reliable, low-noise refrigerators are needed for the cooling of high-Tc SQUID magnetometers. Working toward this goal, J. Gerster (Jena) et al. have developed a low-noise one-stage four-valve pulse-tube refrigerator (FVPTR) with nonmetallic regenerator material, which has reached a temperature below 60 K.

Four other preprints from the Jena group report various developments aimed toward applications of the high-Tc superconductors. Y. J. Tian et al. report the preparation of large-area YBCO thin films by pulsed-laser deposition (PLD) on SrTiO3 substrates and on naturally oxidized two- inch-diameter Si wafers with CeO2/YSZ buffer layers. S. Linzen et al. report on the properties of dc SQUIDs using YBCO with grain-boundary junctions produced on Si bicrystals. F. Schmidl et al. describe the performance of different types of planar high-Tc dc SQUID gradiometers intended for use in a nondestructive testing system. And R. Weidl et al. describe a one-channel heart-monitoring system based on planar, single-layer high-Tc dc SQUID magnetometers and gradiometers which are able to work in an unshielded environment.

Three preprints from Karlsruhe, two by A. Kaiser et al. and one by H. J. Bornemann et al., report on various aspects of the development of batch processing techniques for the fabrication of advanced YBCO bulk materials for industrial applications. Bulk components are produced powder metallurgically and densified by melt texturing. The pellets produced by this technique are suitable for use in flux-trapped magnets and frictionless, self-stabilizing magnetic bearings.

The fabrication of large-domain YBCO levitators for frictionless superconducting magnetic bearings is discussed in a preprint by S. Sengupta et al. (Superconductive Components). The authors describe a method in which a Nd1+xBa2-xCu3Oy single crystal seed is used to initiate grain growth during melt processing. The authors have demonstrated the feasibility of large-scale manufacturing of YBCO levitators in batch sizes of about 90 samples in a furnace.

A preprint by Y. H. Kim (KIST) et al. reports on the operation of a single-flux-quantum (SFQ) logic circuit at 71 K over 200 computer- generated clock cycles without making errors. The device was an SFQ RS flip-flop made with a YBCO thin film deposited on a SrTiO3 bicrystal. The authors found that the effective noise temperature required to fit the data was much higher than the actual temperature.

Other Activities

As reported by T. Henning (Hamburg) et al., the resistivity vs. temperature in bulk ceramic high-temperature superconductors can be modeled by local Lorentz-force-induced fluxon motion with temperature- dependent pinning. To account for both the intergrain and intragrain regions, two pinning force densities and two viscous drag coefficients are needed to characterize the temperature, current, and field dependencies of the sample resistance.

The magnetic and transport properties of granular samples of the electron-doped superconductor Sm1.83C0.17CuO4-y have been studied by M.J.R. Sandim (Lorena) et al. The authors find via magnetic susceptibility measurements that superconductivity appears in the grains at T_[ci] ~~ 17.5 K but that the electrical resistance increases as the temperature drops below T_[ci].

A preprint by S. S. Saxena et al. (Cambridge) reports that the normal- state transport properties of the heavy-fermion compound CeNi2Ge2 are unusual and at variance with those expected of a simple Fermi liquid. Moreover, at pressures above 12 kbar this unconventional normal state gives way to a superconducting transition in the mK temperature range.

Overviews

An extensive survey of the synthesis and structure of the Hg-based cuprates Hg-12(n-1)n and Hg-22(n-1)n as of April 1997 has been prepared by S. M. Loureiro (CNRS-Grenoble). The author also reports on pressure effects (on resistivity and structure) and substitutions in these materials (280 refs.).

Superconducting condensate formation in metallic systems with a variable density of carriers is discussed in a theoretical overview by V. M. Loktev (Kyiv) and S. E. Sharapov (Pretoria). The authors discuss the crossover from Bose-Einstein condensation (BEC) at low density to Bardeen-Cooper-Schrieffer (BCS) condensation at high density. The authors also discuss the connections between their theory and experimental observations of a pseudogap (73 refs.).

Ph.D. Theses

Magnetization measurements in single-crystal Bi2Sr2CaCu2O8+d (Bi-2212) are reported in the Cambridge Ph.D. thesis of C. Dewhurst. The thesis contributes to a fuller understanding of the field-temperature (H-T) phase diagram and the effects of pinning centers due to irradiation or anisotropy changes due to intercalation. The author presents data showing that while heavy-ion irradiation enhances Jc and the irreversibility line over a substantial region of the H-T plane, iodine intercalation is detrimental to the superconducting properties of Bi- 2212 (243 refs.).

Investigations of thin films and different types of Josephson junctions based on Bi-2212 superconductors are reported in the Jena Ph.D. thesis of A. Pfuch. The author prepared Bi-2212 thin films by laser ablation, investigated grain-boundary Josephson junctions, and fabricated dc SQUIDs. The author also developed a technology for the preparation of intrinsically stacked Josephson junctions and investigated the properties of devices using such junctions (158 refs.).

Contributed by John R. Clem

Contents: Preprints begin on page 4; Coming Events are on page 15; and FYI is on page 15.

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.

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.

M. V. Abrashev, C. Thomsen, and M. Surtchev, "Doping Effects in the Sr14Cu24O41-Type Structure: A Raman Scattering Study." To be published in Physica C (in press). Institut fuer Festkoerperphysik, Technische Universitaet Berlin, Hardenbergstrasse 36, D-10623 Berlin, GERMANY; telephone +49 30 314 24262; telefax +49 30 314 27705; e-mail abrashev@mail.physik.tu-berlin.de. Key words: Raman spectroscopy, spin-ladder compounds.

M. K. Al-Mosawi, A. Crisan, C. Beduz, D. Phillips, and P. Haldar, "Current-Voltage Characteristics of Long Bi2Sr2Ca2Cu3O10/Ag Multifilamentary Tapes at Different Bending Strains." To be published in Physica C. Contact A. Crisan, Institute of Cryogenics, University of Southampton, Southampton SO17 1BJ, UNITED KINGDOM; telefax +44 1703 593053; e-mail a.i.crisan@soton.ac.uk. Key words: multifilamentary tapes, I-V curves, bending strain, vortex fluctuations.

M. Aprili, M. Covington, E. Paraoanu, B. Niedermeier, and L. H. Greene, "Lifetime of the Quasiparticle Andreev Bound State in Ion-Irradiated YBa2Cu3O7-d/Pb Junctions." Contact L. H. Greene, Department of Physics, Loomis Laboratory of Physics, University of Illinois at Urbana- Champaign, 1110 West Green Street, Urbana, IL 61801-3080; telephone (217) 333-7315; telefax (217) 244-7187; e-mail lhg@uiuc.edu. 73.40.Gk; 74.50.+r; 74.76.Bz; 81.40.Wx.

Adolfo Avella, Ferdinando Mancini, Dario Villani, and Hideki Matsumoto, "The Two-Dimensional t-t'-U Model as a Minimal Model for Cuprate Materials." Submitted to Phys. Rev. B. Dipartimento di Scienze Fisiche "E.R. Caianiello", Unita INFM di Salerno, Universita degli Studi di Salerno, I-84081 Baronissi (SA), ITALY; telephone +39 89 965422; telefax +39 89 965275; e-mail aveado@vaxsa.csied.unisa.it; preprint also available at cond-mat@xxx.lanl.gov (#9707088). 71.10.Fd.

D. A. Beam, N.-C. Yeh, and F. Holtzberg, "Universal Vortex-State Hall Conductivity of YBa2Cu3O7 Single Crystals with Different Correlated Disorder." Submitted to Phys. Rev. Lett. Department of Physics, California Institute of Technology, Pasadena, CA 91125. 74.60.Ge; 74.60.Ec; 74.25.Dw; 74.72.Bk.

F. Becca, F. Bucci, and M. Grilli, "The Incommensurate Charge-Density- Wave Instability in the Extended Three-Band Hubbard Model." Istituto Nazionale di Fisica della Materia and Dipartimento di Fisica, Universita di Roma "La Sapienza," Piazzale A. Moro 2, I-00185 Roma, ITALY; M. Grilli's e-mail marco.grilli@roma1.infn.it; preprint also available at cond-mat@xxx.lanl.gov (#9707109).

Maamar Benkraouda and John R. Clem, "Critical Current from the Geometrical Barrier in Type-II Superconducting Strips." Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, IA 50011-3160; John R. Clem's telephone (515) 294-4223; telefax (515) 294- 0689; e-mail clem@ameslab.gov.

P. Berghuis, E. Di Bartolomeo, G. A. Wagner, and J. E. Evetts, "Intrinsic Channelling of Vortices Along the ab-Plane in Vicinal YBa2Cu3O7-d Films." To be published in Phys. Rev. Lett. Department of Materials Science and Metallurgy and IRC in Superconductivity, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ, UNITED KINGDOM; telephone +44 1223 334375; telefax +44 1223 334373; e-mail pb10020@cam.ac.uk. 74.60.Ge; 74.25.Ha; 74.76.Bz; 74.72.Bk.

N. A. Bert, A. V. Lunev, Yu. G. Musikhin, R. A. Suris, V. V. Tret'yakov, A. V. Bobyl, S. F. Karmanenko, and A. I. Dedoborez, "Mechanisms of Cation Defect Formation in Epitaxial YBa2Cu3O7-x Films." To be published in Physica C (in press). A. F. Ioffe Institute, 26 Polytechnicheskaya, St. Petersburg 194021, RUSSIA. Key words: cation defects, electron microanalysis, triple phase diagram, local critical temperature.

A. Bill, V. Hizhnyakov, D. Nevedrov, G. Seibold, and E. Sigmund, "Electronic Inhomogeneities, Electron-Lattice and Pairing Interactions in High-Tc Superconductors." To be published in Z. Phys. B: Proc. of the 11th Workshop on Electron-Phonon Interaction and Phase Transitions, Erice, Italy, June 1997. Lawrence Berkeley Laboratory, University of California, MS 62-203, 1 Cyclotron Road, Berkeley, CA 94720; telephone (510) 486-6991; telefax (510) 486-5401; e-mail abill@lbl.gov.

A. Bill, V. Z. Kresin, and S. A. Wolf, "Isotope Effect in High-Tc Materials: Role of Non-Adiabaticity and Magnetic Impurities." To be published in Z. Phys. B: Proc. of the 11th Workshop on Electron-Phonon Interaction and Phase Transitions, Erice, Italy, June 1997. Lawrence Berkeley Laboratory, University of California, MS 62-203, 1 Cyclotron Road, Berkeley, CA 94720; telephone (510) 486-6991; telefax (510) 486- 5401; e-mail abill@lbl.gov.

E. V. Blinov, V. G. Fleisher, R. Laiho, E. Laehderanta, Yu. P. Stepanov, K. B. Traito, "Dependence of the Meissner Penetration Length in Submicron Vortex-Free and Vortex-Trapped Y-Ba-Cu-O Particles: Test for Applicability of the Modified London Equation." To be published in Physica C (in press). Contact E. Laehderanta, Wihuri Physical Laboratory, University of Turku, FIN-20014 Turku, FINLAND; telefax +358 2 231 9836; e-mail erkki.lahderanta@utu.fi. Key words: London penetration depth, magnetization, Meissner effect, mixed state. 74.25.Ha; 74.20.De; 74.80.Bj.

Hans J. Bornemann, A. Kaiser, M. Adam, and Th. Burghardt, "Towards Commercialization of HTS Products: Batch Processing of Advanced HTS Bulk at Forschungszentrum Karlsruhe GmbH." Presented at the Third Joint ISTEC/MRS Int. Workshop on Supercond., Big Island, Hawaii, June 15-18, 1997. Contact A. Kaiser, Forschungszentrum Karlsruhe GmbH, INFP, P.O. Box 3640, D-76021 Karlsruhe, GERMANY; telephone +49 7247 82 3981; telefax +49 7247 82 4624; e-mail axel.kaiser@infp.fzk.de; Web site http://www.infp.fzk.de.

H. Bougrine, M. Houssa, R. Cloots, M. Pekala, I. Sargankova, and M. Ausloos, "Transport Properties of HgBaCaCuO(1223) Polycrystalline Superconductors." Submitted to Supercond. Sci. & Technol.: Proc. of Supercond. Mater. Aspects--Res. & Technol. (SMART 97), Liege, Belgium, June 26-29, 1997. SUPRAS, Montefiore Electricity Institute B28, University of Liege, B-4000 Liege, BELGIUM; e-mail hassan@montefiore.ulg.ac.be.

W. K. Chu, Y. P Li, J. R. Liu, J. Z. Wu, S. C. Tidrow, N. Toyoda, J. Matsuo, and I. Yamada, "Smoothing of YBCO Films by Ion Cluster Beam Bombardment." Preprint #97:075; submitted to Appl. Phys. Lett. Texas Center for Superconductivity, University of Houston, Houston, TX 77204- 4792; telephone (713) 743-4514; telefax (713) 743-4513; preprints also available at e-mail preprints@www.tcs.uh.edu or wkchu@uh.edu.

M. Daeumling, "Numerical Calculation of ac Losses, Field and Current Distributions for Specimens with Demagnetization Effects." Presented at the 3rd European Conf. on Appl. Supercond. (EUCAS'97), Veldhoven, The Netherlands, June 30-July 3, 1997. Forschungszentrum Karlsruhe, Institut fuer Technische Physik, P.O. Box 3640, D-76021 Karlsruhe, GERMANY.

P. Singha Deo, V. A. Schweigert, F. M. Peeters, and A. K. Geim, "Magnetization of Mesoscopic Superconducting Discs." Department of Physics, University of Antwerp (UIA), B-2610 Antwerpen, BELGIUM; e-mail deo@uia.ua.ac.be; preprint also available at cond-mat@xxx.lanl.gov (#9707025). 74.25.Ha; 74.60.Ec; 74.80.-g.

Charles David Dewhurst, "Magnetization Measurements of High Temperature Superconducting Single Crystal Bi2Sr2CaCu2O8+d." Submitted as a Ph.D. thesis (University of Cambridge). Interdisciplinary Research Centre in Superconductivity, University of Cambridge, West Cambridge Site, Madingley Road, Cambridge CB3 0HE, UNITED KINGDOM; telephone +44 1223 337441; telefax +44 1223 337074; e-mail cdd1001@cus.cam.ac.uk; Web site http://www.sucon.cam.ac.uk/staff/charles_dewhurst/cdd-home.htm.

Pavel Diko, "Cracking in Melt-Processed RE-Ba-Cu-O Superconductors." To be published in Supercond. Sci. & Technol.: Proc. of Supercond. Mater. Aspects--Res. & Technol. (SMART 97), Liege, Belgium, June 26-29, 1997. Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 04353 Kosice, SLOVAKIA; e-mail dikos@linux1.saske.sk.

Pavel Diko, Christian Wende, Doris Litzkendorf, Thomas Klupsch, and Wolfgang Gawalek, "The Influence of Starting Y123 Particle Size and Pt/Ce Addition on the Microstructure of Y123-211 Melt Processed Bulks." To be published in Supercond. Sci. & Technol.: Proc. of Supercond. Mater. Aspects--Res. & Technol. (SMART 97), Liege, Belgium, June 26-29, 1997. Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 04353 Kosice, SLOVAKIA; e-mail dikos@linux1.saske.sk.

Sasa Dukan and Zlatko Tesanovic, "Density of States of a Type-II Superconductor in a High Magnetic Field: Impurity Effects." To be published in Phys. Rev. B. Department of Physics and Astronomy, Goucher College, Baltimore, MD 21204; e-mail dukan@django.pha.jhu.edu; preprint also available at cond-mat@xxx.lanl.gov (#9706290). 72.20.My; 71.45.-d; 71.30.+h.

H. Eckelmann, M. Daeumling, M. Quilitz, and W. Goldacker, "Investigations of the ac Current Loss of Twisted and Untwisted Multifilamentary Ag/, AgMg/, and AgAu/ Bi(2223) Tapes." Presented at the 3rd European Conf. on Appl. Supercond. (EUCAS'97), Veldhoven, The Netherlands, June 30-July 3, 1997. Forschungszentrum Karlsruhe, Institut fuer Technische Physik, P.O. Box 3640, D-76021 Karlsruhe, GERMANY; telephone +49 7247 82 5341; telefax +49 7247 82 5398; e-mail hubert.eckelmann@itp.fzk.de.

D. Fuchs, E. Brecht, P. Schweiss, I. Loa, C. Thomsen, and R. Schneider, "Growth and Characterization of a-Axis Oriented YBa2Cu3O7-x Thin Films on (100) LaSrGaO4 Substrates." To be published in Physica C (in press). Forschungszentrum Karlsruhe, Institut fuer Nukleare Festkoerperphysik, P.O. Box 3640, D-76021 Karlsruhe, GERMANY; telephone +49 7247 28 3985; telefax +49 7247 82 4624; e-mail dfuchs@infp.fzk.de.

S. Fujihara, Y. Masuda, J.-S. Jin, T. Kimura, and K. Tanabe, "A Novel Sol-Gel Route to Superconducting Oxyfluoride Sr2Cu(O,F)y Thin Films." To be published in Physica C (in press). Department of Applied Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223, JAPAN; telefax +81 45 562 7625; e-mail shinobu@applc.keio.ac.jp. Key words: oxyfluoride superconductor, Sr2Cu(O,F)y, Sr2CuO2F2+d, sol gel, thin films.

T. Fukunaga and A. Oota, "ac Transport Losses under Self Fields in Ag- Sheathed (Bi,Pb)2Sr2Ca2Cu3Ox Conductors." To be published in Physica C. Contact A. Oota, Toyohashi University of Technology, Tempaku-cho, Toyohasi, Aichi 441, JAPAN; telefax +81 532 44 6732; e-mail oota@eee.tut.ac.jp. Key words: ac transport losses, self fields, multifilamentary tape, twist, parallel conductors. 74.60.Ge; 74.60.Jg; 74.70.-b.

A. Agliolo Gallitto, I. Ciccarello, M. Guccione, M. Li Vigni, and D. Persano Adorno, "Field-Induced Variations of the Microwave Surface Impedance of YBa2Cu3O7 Crystals Near Tc." To be published in Phys. Rev. B. Istituto Nazionale de Fisica della Materia, Unita di Palermo and Istituto di Fisica dell'Universita, Via Archirafi 36, I-90123 Palermo, ITALY. 74.25.Nf; 74.20.De; 74.60.Ec.

J. Gerster, L. Reissig, I. Ruehlich, M. Thuerk, and P. Seidel, "Four- Valve Pulse Tube Refrigerator (FVPTR) with Non-Metallic Regenerator Material." Submitted to the Proc. of the 3rd European Conf. on Appl. Supercond. (EUCAS'97), Veldhoven, The Netherlands, June 30-July 3, 1997. Institut fuer Festkoerperphysik, Friedrich-Schiller-Universitaet Jena, Lessingstrasse 8, D-07743 Jena, GERMANY; P. Seidel's telephone +49 3641- 635685 or -635681; telefax +49 3641-635681; e-mail seidel@ifk.uni- jena.de.

E. Goodilin, M. Kambara, T. Umeda, and Y. Shiohara, "Construction of a Quasi-Ternary Phase Diagram in the NdO1.5-BaO-CuO System in the Air Atmosphere -- Part II: Phase Equilibria of the Neodymium-Rich Nd1+xBa2- xCu3Oz Solid Solution." To be published in Physica C (in press). Superconductivity Research Laboratory, International Superconductivity Technology Center (ISTEC), 1-10-13 Shinonome, Koto-ku, Tokyo 135, JAPAN; telefax +81 3 3536 5714. Key words: neodymium solid solution, liquidus, phase diagram.

K. C. Goretta, Y. Xu, R. E. Cook, L. R. Feng, A. Deptula, W. Lada, T. Olczak, M. Xu, and U. Balachandran, "Synthesis and Properties of a Bi2Sr2CaCu2Ox-BaTiO3 Composite Powder." Submitted to Supercond. Sci. & Technol. Contact Janice Coble, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439; telefax (708) 252-9595; e-mail janice_coble@qmgate.anl.gov.

B. Gu, P. E. Phelan, and S. Mei, "Coupled Heat Transfer and Thermal Stress in High-Tc Thin-Film Superconductor Devices." To be published in Cryogenics. Contact P. E. Phelan, Department of Mechanical and Aerospace Engineering, Arizona State University, P.O. Box 876106, Tempe, AZ 85287-6106; telephone (602) 965-1625; telefax (602) 965-1384; e-mail phelan@asu.edu.

Damian P. Hampshire, "Critical Currents and the Critical State in Superconductors with Magnetic Ions." To be published in Physica C (in press). Superconductivity Group, Department of Physics, University of Durham, South Road, Durham DH1 3LE, UNITED KINGDOM; telephone +44 191 374 2167; telefax +44 191 374 3749. 74.60.Jg; 74.25.Ha.

Nobuhiko Hayashi, Masanori Ichioka, and Kazushige Machida, "Effects of Gap Anisotropy upon the Electronic Structure Around a Superconducting Vortex." To be published in Phys. Rev. B. Department of Physics, Okayama University, Okayama 700, JAPAN; telefax +81 86 252 7595; e-mail hayashi@mp.okayama-u.ac.jp; Web site http://mp.okayama- u.ac.jp/~hayashi/vortex.html; preprint also available at cond- mat@xxx.lanl.gov (#9705286). 74.60.Ec; 61.16.Ch; 74.25.Jb.

Torsten Henning, D. B. Haviland, and P. Delsing, "Coulomb Blockade Effects in Anodised Niobium Nanostructures." To be published in Supercond. Sci. & Technol. Department of Physics, Chalmers University of Technology and University of Goeteborg, Fysikgraend 3, SE-41296 Goeteborg, SWEDEN; telephone +46 31 772 3678; telefax +46 31 772 3471; e-mail henning@fy.chalmers.se; Web site http://fy.chalmers.se/~henning; preprint also available at cond-mat@xxx.lanl.gov (#9706302).

Torsten Henning, H. Kliem, A. Weyers, and W. Bauhofer, "Characterization of HTSC Ceramics from their Resistive Transition." To be published in Supercond. Sci. & Technol. Department of Physics, Chalmers University of Technology and University of Goeteborg, Fysikgraend 3, SE-41296 Goeteborg, SWEDEN; telephone +46 31 772 3678; telefax +46 31 772 3471; e-mail henning@fy.chalmers.se; Web site http://fy.chalmers.se/~henning; preprint also available at cond-mat@xxx.lanl.gov (#9707165).

G. Hollauer and Mauro M. Doria, "Properties of High-Tc Single Crystals as Natural Interferometers in the THz Frequency Range." Departamento de Fisica, Pontificia Universidade Catolica do Rio de Janeiro, Rio de Janeiro, 22452-970 RJ, BRAZIL; e-mail gilho@fis.puc-rio.br; preprint also available at cond-mat@xxx.lanl.gov (#9706184).

Carsten Honerkamp and Manfred Sigrist, "Andreev Reflection in Unitary and Non-Unitary Triplet States." Institute of Theoretical Physics, ETH Hoenggerberg, CH-8093 Zurich, SWITZERLAND; e-mail chonerka@itp.phys.ethz.ch; preprint also available at cond- mat@xxx.lanl.gov (#9706199).

A. M. Hu, Z. X. Zhao, J. W. Xiong, and C. Pang, "Effects of Nd4Ba2Cu2Oy Phase on Texturing and Properties of Melt-Textured NdBa2Cu3Oy." To be published in Physica C. National Laboratory for Superconductivity, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, PEOPLE'S REPUBLIC OF CHINA; telefax +86 10 6256 8834; e-mail shx@aphy01.iphy.ac.cn. Key words: melt-textured materials, NdBa2Cu3Oy, levitation force.

Xing Hu, Y. Xin, and K. W. Wong, "Influence of the Mass Density on the Critical Current Density of the Bulk Tl2Ba2Ca2Cu3O10 Material." To be published in Physica C (in press). Department of Physics, Zhengzhou University, Zhengzhou, Henan, PEOPLE'S REPUBLIC OF CHINA. Key words: critical current density, granular superconductivity, weak links. 74.60.Jg.

Y. T. Huang and L. J. Chen, "Microstructural Evolution and the Role of Pb Atmosphere in Forming Bi-2223 Superconductor." To be published in Physica C (in press). Contact L. J. Chen, Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300, Taiwan, REPUBLIC OF CHINA; telephone +886 3 571 8328; telefax +886 3 571 8328; e-mail ljchen@mse.nthu.edu.tw. Key words: Bi-2223, structural phase transformation, Pb atmosphere, microstructure.

K. C. Hung, C. C. Lam, X. Jin, J. Feng, and H. M. Shao, "Vortex Dynamics in Pb-Doped Hg-1234 Superconductor by ac Susceptibility Response." To be published in Physica C (in press). Contact C. C. Lam, Department of Physics and Materials Science, City University of Hong Kong, Kowloon, HONG KONG; telephone +852 2788 7831; telefax +852 2788 7830; e-mail apcclam@cityu.edu.hk. 74.60.Ge; 74.60.Jg.

Y. Imagawa, K. Kakimoto, and Y. Shiohara, "Effect of Unidirectional Solidification Rate on Jc for Current Lead." To be published in Physica C (in press). Superconductivity Research Laboratory, International Superconductivity Technology Center (ISTEC), 1-10-13 Shinonome, Koto-ku, Tokyo 135, JAPAN; telephone +81 3 3536 5711; telefax +81 3 3536 5705. Key words: directional solidification, YBCO, high Jc, traveling rate, nominal composition, current lead.

Yoshiaki Ito, Yutaka Yoshida, Morihiro Iwata, Yoshiaki Takai, and Izumi Hirabayashi, "Preparation of Double-Sided YBa2Cu3O7-d Film by Hot-Wall Type MOCVD." To be published in Physica C. Superconductivity Research Laboratory, International Superconductivity Technology Center (ISTEC), Nagoya 456, JAPAN. Key words: YBa2Cu3O7-d, MOCVD, liquid sources, fiber, double sided.

A. W. Kaiser, M. Adam, and H. J. Bornemann, "Characterization and Properties of Batch Processed Melt-Textured YBCO." Presented at Supercond. Mater. Aspects--Res. & Technol. (SMART 97), Liege, Belgium, June 26-29, 1997. INFP, Forschungszentrum Karlsruhe GmbH, P.O. Box 3640, D-76021 Karlsruhe, GERMANY; telephone +49 7247 82 3981; telefax +49 7247 82 4624; e-mail axel.kaiser@infp.fzk.de; Web site http://www.infp.fzk.de.

A. W. Kaiser, H. J. Bornemann, and R. Koch, "Processing Technique for Fabrication of Advanced YBCO Bulk Materials for Industrial Applications." Presented at the 3rd European Conf. on Appl. Supercond. (EUCAS'97), Veldhoven, The Netherlands, June 30-July 3, 1997. INFP, Forschungszentrum Karlsruhe GmbH, P.O. Box 3640, D-76021 Karlsruhe, GERMANY; telephone +49 7247 82 3981; telefax +49 7247 82 4624; e-mail axel.kaiser@infp.fzk.de; Web site http://www.infp.fzk.de.

B. W. Kang, W. N. Kang, S. H. Yun, and J. Z. Wu, "Scaling Behavior of Activation Energy of HgBa2CaCu2O6+d Thin Films." Preprint #97:070; to be published in Phys. Rev. B. Department of Physics and Astronomy, University of Kansas, Lawrence, KS 66045; e-mail kang@kuphsx.phsx.ukans.edu; preprint also available from 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.

P. E. Kazin, V. V. Poltavets, Y. D. Tretyakov, M. Jansen, B. Freitag, and W. Mader, "Study on the Superconducting Composite Material Formation in the System Bi2Sr2CaCu2O8+x/Al-Containing Phases." To be published in Physica C (in press). Department of Chemistry , Moscow State University, 119899 Moscow, RUSSIA; telephone +7 095 9393440; telefax +7 095 9390998; e-mail kazin@tret.chem.msu.su. Key words: Bi2Sr2CaCu2O8+x, foreign phase inclusions, phase formation, microstructure, flux pinning.

Y. H. Kim, J. H. Kang, J. M. Lee, T. S. Hahn, S. S. Choi, and S. J. Park, "Operation of High-Tc SFQ Devices at Near Liquid Nitrogen Temperature." To be published in Physica C (in press). Applied Physics Laboratory, KIST, P.O. Box 131, Cheongryang, Seoul 130-650, KOREA; telephone +82 2 9585722; telefax +82 2 9585789; e-mail youngkim@kistmail.kist.re.kr. Key words: applications of high-Tc superconductors, single flux quantum (SFQ), noise effect.

P. Konsin, B. Sorkin, and M. Ausloos, "3D Fluctuation Conductivity in the Two-Band Model: Theory and Experiment." Submitted to Supercond. Sci. & Technol.: Proc. of Supercond. Mater. Aspects--Res. & Technol. (SMART 97), Liege, Belgium, June 26-29, 1997. Institute of Physics, Riia 142, EE2400 Tartu, ESTONIA. 74.72.Dn; 74.72.Bk; 74.72.Hs; 74.76.- w; 74.40.+k.

Martin Kupka, "Current-Voltage Characteristic and Differential Conductance of a Point Contact and Planar Tunnel Contact Between an Ordinary Metal and Superconductor in Realistic Three-Dimensional Geometry: Comparison with a One-Dimensional Case." To be published in Physica C (in press). Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 04353 Kosice, SLOVAK REPUBLIC; e-mail kupkam@linux1.saske.sk. Key words: tunneling, superconducting microconstriction, N-S interface.

A. V. Kuznetsov, D. V. Eremenko, and V. N. Trofimov, "Onset of Flux Penetration into a Type-II Superconductor Disk." To be published in Phys. Rev. B. Department of Quantum Electronics, Moscow State Engineering Physics Institute, Kashirskoe shosse 31, 115409 Moscow, RUSSIA; telephone +7 095 323 9386; telefax +7 095 324 2111; e-mail kuzn@htsc.mephi.ru. 74.60.Ec; 74.60.Ge; 74.72.-h.

K. Kwasnitza, St. Clerc, R. Fluekiger, Y. B. Huang, and G. Grasso, "ac Losses of Twisted High-Tc Superconducting Multifilament Bi2223 Tapes with a Mixed Matrix of Ag and BaZrO3." Presented at the 3rd European Conf. on Appl. Supercond. (EUCAS'97), Veldhoven, The Netherlands, June 30-July 3, 1997. Paul Scherrer Institut, CH-5232 Villigen PSI, SWITZERLAND; telephone +41 56 310-2111 or -3593; telefax +41 56 310-2199 or -3131.

Yu-Liang Lai, Teng-Ming Chen, J. T. Shih, and H.-C.I. Kao, "The High Pressure Synthesis and Characterization of Some Rare-Earth Based Praseodymium-Substituted R2Ba4Cu7O14+d (R=Sm,Gd,Ho) Cuprates." To be published in Physica C (in press). Contact Teng-Ming Chen, Department of Applied Chemistry, National Chiao-Tung University, Hsinchu 300, Taiwan, REPUBLIC OF CHINA; telephone +886 35 712121, ext. 56501; telefax +886 35 723764; e-mail tmchen@cc.nctu.edu.tw or tmchen@scl.kyoto- u.ac.jp. Key words: substitution effect, Meissner effect, high- pressure synthesis of (R,Pr)2Ba4Cu7O14+d.

M. Leghissa, J. Rieger, J. Wiezoreck, H.-P. Kraemer, B. Roas, B. Fischer, K. Fischer, and H.-W. Neumueller, "Development of HTS Tapes and Multistrand Conductors for Power Transmission Cables." Presented at the 3rd European Conf. on Appl. Supercond. (EUCAS'97), Veldhoven, The Netherlands, June 30-July 3, 1997. Siemens AG, Corporate Technology, P.O. Box 3220, D-91050 Erlangen, GERMANY; telephone +49 9131 7 32634; telefax +49 9131 7 33323; e-mail martino.leghissa@erls.siemens.de.

Dong Ming Li, Du Hong Shan, Du Shu Bin, Li Jian Hua, Jiang Yong, Tong Bo Ting, and Che Guang Can, "Electric Field Gradient Measurements on [111]^Cd in the High-Tc Superconductor Bi1.7Pb0.3Sr2Ca2Cu3Oy." To be published in Physica C (in press). Institute of Atomic Energy, 102413 Beijing, PEOPLE'S REPUBLIC OF CHINA. Key words: superconductor, electric field gradients, perturbed angular correlations.

Y. P. Li, J. R. Liu, W. K. Chu, and T. J. Tate, "Observation of Dynamic Annealing Effects in Oxide Single Crystals After High Dose [18]^O^+ Implantation at 500^oC." Preprint #97:069; submitted to Phys. Rev. B. Texas Center for Superconductivity, University of Houston, Houston, TX 77204-4792; telephone (713) 743-4514; telefax (713) 743-4513; preprint also available at preprints@www.tcs.uh.edu.

S. Linzen, F. Schmidl, Y. Tian, U. Huebner, T. Koehler, R. Cihar, and P. Seidel, "HTSC SQUIDs on Technical Substrates." Presented at the 3rd European Conf. on Appl. Supercond. (EUCAS'97), Veldhoven, The Netherlands, June 30-July 3, 1997. Institut fuer Festkoerperphysik, Friedrich-Schiller-Universitaet Jena, Lessingstrasse 8, D-07743 Jena, GERMANY; P. Seidel's telephone +49 3641-635685 or -635681; telefax +49 3641-635681; e-mail seidel@ifk.uni-jena.de.

Vadim M. Loktev and Sergei G. Sharapov, "Superconducting Condensate Formation in Metallic Systems with Arbitrary Carrier Density." To be published in Cond. Mat. Phys. Bogolyubov Institute for Theoretical Physics, National Academy of Sciences of Ukraine, 14-b Metrologichna Str., 252143 Kyiv-143, UKRAINE; e-mail vloktev@gluk.apc.org; preprint also available at cond-mat@xxx.lanl.gov (#9706285).

S. M. Loureiro, C. Chaillout, E. Gautier, J. J. Capponi, P. Toulemonde, E. V. Antipov, J. L. Tholence, and M. Marezio, "Synthesis, Structural and Magnetic Characterization of New Hg2Ba2LnCu2O8-d Phases with Ln=Nd- Gd, Dy-Lu." To be published in J. Solid State Chem. Laboratoire de Cristallographie, CNRS, BP 166, F-38042 Grenoble Cedex 09, FRANCE; telefax +33 4 7688 1038; e-mail loureiro@labs.polycnrs-gre.fr. Key words: Hg-based Cu-mixed oxides, x-ray power diffraction, ac susceptibility.

A. G. Mamalis, I. Kotsis, G. Pantazopoulos, M. Enisz, A. Szalay, and D. E. Manolakos, "The Effect of Heat Treatment on Explosively Compacted (Y- Ba-K-Cu-O) Superconductive Powders." To be published in Physica C (in press). Department of Mechanical Engineering, National Technical University of Athens, 106 82 Athens, GREECE; telephone +30 1 7723688; telefax +30 1 7723689; e-mail mamalis@naxos.esd.ece.ntua.gr.

Chuanbin Mao, Lian Zhou, and Xiangyun Sun, "Interaction Between BiPbSrCaCuO Powder and Ambient Atmosphere." To be published in Physica C (in press). Superconducting Material Research Center, Northwest Institute for Nonferrous Metal Research, P.O. Box 71, Baoji Shaanxi 721014, PEOPLE'S REPUBLIC OF CHINA; telephone +86 917 338 2648; telefax +86 917 338 2001. Key words: BiPbSrCaCuO, powder adsorption, FTIR, XPS, AES.

Chuanbin Mao, Lian Zhou, and Xiangyun Sun, "Optimization of the Solution-Sol-Gel Process to Synthesize Homogeneous BiPbSrCaCuO Powder." To be published in Physica C (in press). Superconducting Material Research Center, Northwest Institute for Nonferrous Metal Research, P.O. Box 71, Baoji Shaanxi 721014, PEOPLE'S REPUBLIC OF CHINA; telephone +86 917 338 2648; telefax +86 917 338 2001. Key words: solution-sol-gel (SSG), BiPbSrCaCuO powder.

Chuanbin Mao, Lian Zhou, Xiangyun Sun, and Xiaozu Wu, "Coprecipitation- Based Micro-Reactor Process to Synthesize Soft-Agglomerated Ultrafine BiPbSrCaCuO Powder with Low Carbon Content." To be published in Physica C (in press). Superconducting Material Research Center, Northwest Institute for Nonferrous Metal Research, P.O. Box 71, Baoji Shaanxi 721014, PEOPLE'S REPUBLIC OF CHINA; telephone +86 917 338 2648; telefax +86 917 338 2001. Key words: BiPbSrCaCuO, superconductor, coprecipitation-based micro-reactor process (CMP).

Chuanbin Mao, Lian Zhou, Xiaozu Wu, and Xiangyun Sun, "New Understanding of Silver-Induced Texture in Powder-in-Tube Processed Ag/Bi(2223) Tape." To be published in Physica C (in press). Superconducting Material Research Center, Northwest Institute for Nonferrous Metal Research, P.O. Box 71, Baoji Shaanxi 721014, PEOPLE'S REPUBLIC OF CHINA; telephone +86 917 338 2648; telefax +86 917 338 2001. Key words: silver-induced texture, reaction-induced texture, auger electron spectroscopy, x-ray photoelectron spectroscopy, (Bi,Pb)2Sr2Ca2Cu3Ox(2223).

K. N. Marimuthu, M. S. Ramachandra Rao, and U. V. Varadaraju, "Phase Formation and Superconductivity in REBaSrCu3-x(PO4)xOy (0 <= x <= 0.3)." To be published in Physica C (in press). Contact U. V. Varadaraju, Materials Science Research Centre, Indian Institute of Technology, Madras 600 036, INDIA; telefax +91 44 235 0509; e-mail raju@msrc.iitm.ernet.in. Key words: oxy-anion superconductor, ac susceptibility, electrical resistivity, infrared spectroscopy.

W. Markowitsch, C. Stockinger, W. Lang, K. Bierleutgeb, J. D. Pedarnig, and D. Baeuerle, "Photoinduced Enhancement of the c-Axis Conductivity in Oxygen-Deficient YBa2Cu3Ox Thin Films." To be published in Appl. Phys. Lett. Ludwig Boltzmann Institut fuer Festkoerperphysik, Kopernikusgasse 15, A-1060 Wien, AUSTRIA.

I. I. Mazin and A. I. Liechtenstein, "Where Are Holes in Y1- xPrxBa2Cu3O7?" Code 6691, Naval Research Laboratory, Washington, DC 20375; e-mail mazin@dave.nrl.navy.mil; preprint also available at cond- mat@xxx.lanl.gov (#9706259).

R. L. Meng, Y. Q. Wang, K. Lewis, C. Garcia, Y. Cao, and C. W. Chu, "Hg- 1223 Thick Film on Flexible Ni Substrates." Preprint #97:071; to be published in J. Supercond.: Proc. of the Int. Workshop on Tl- and Hg- Based Supercond. Mater., Cambridge, United Kingdom, May 25-28, 1997. 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. Key words: Hg-1223, Hg-1212, Ni-substrates, Jc, thick film.

Sang Boo Nam, "New Vortex with Zero Fluxoid Quantum in a Superconductor: Anomalous Hall Effect in High Tc and Low Tc Superconductors." Department of Physics, Pohang University of Science and Technology, Pohang, Kyungbook 790-784, KOREA; e-mail sbnam@galaxy.postech.ac.kr; preprint also available at cond-mat@xxx.lanl.gov (#9707004). Key words: superconductivity, vortex, zero fluxoid quantum, Hall effect. 74.60.-w; 74.60.Ge; 74.76.-w.

A. Odagawa, M. Sakai, H. Adachi, and K. Setsune, "Characteristics of Intrinsic Tunnel Junctions on Bi-2223 Thin Films." Submitted to the Proc. of the 6th Int. Supercond. Electronics Conf. (ISEC'97), Berlin, Germany, June 26-28, 1997. Central Research Laboratories, Matsushita Electric Industrial Co., Ltd., 3-4 Hikaridai, Seika, Soraku, Kyoto 619- 02, JAPAN; telephone +81 774 98 2514; telefax +81 774 98 2585.

A. Oota, K. Kawano, and T. Fukunaga, "Self Fields and Current Distribution Due to dc Transport Currents on Ag-Sheathed (Bi,Pb)2Sr2Ca2Cu3Ox Tapes." To be published in Physica C. Toyohashi University of Technology, Tempaku-cho, Toyohashi, Aichi 441, JAPAN; telefax +81 532 44 6732; e-mail oota@eee.tut.ac.jp. Key words: scanning hall sensor, self fields, transport currents, Ag-sheathed tape, Bi2223. 74.60.Jg; 74.72.Hs; 74.76.Bz; 74.60.Ge.

S. K. Patapis, E. Moraitakis, G. Vekinis, D. Niarchos, and P. Clippe, "Percolation Conductivity and Fractal Behavior in an YBaCuO Sample." To be published in Mod. Phys. Lett. B. Department of Physics, Solid State Section, University of Athens, Panepistimiopolis, Athens, GREECE.

Andreas Pfuch, "Investigations on Thin Films and Different Types of Josephson Junctions Based on 2212 High Temperature Superconductors." Submitted as a Ph.D. thesis (Friedrich-Schiller-Universitaet Jena). Institut fuer Festkoerperphysik, Friedrich-Schiller-Universitaet Jena, Lessingstrasse 8, D-07743 Jena, GERMANY.

A. I. Posazhennikova and M. V. Sadovskii, "Ginzburg-Landau Expansion and the Slope of the Upper Critical Field in Superconductors with Anisotropic Normal Impurity Scattering." To be published in JETP. Institute for Electrophysics, Ural Branch of the Russian Academy of Sciences, 620049 Ekaterinburg, RUSSIA; telephone +7 343 2 499 087; telefax +7 343 2 745 051; e-mail posazhen@ief.intec.ru; M. V. Sadovskii's e-mail sadovski@ief.intec.ru; preprint also available at cond-mat@xxx.lanl.gov (#9706240). 74.20.Fg; 74.20.De.

C. Prouteau, K. Verbist, J. F. Hamet, B. Mercey, M. Hervieu, B. Raveau, and G. Van Tendeloo, "Microstructure of a-Axis Oriented YBCO Films on SrTiO3 Substrates Using a New Template Layer La4BaCu5O13." To be published in Physica C. Contact J. F. Hamet, CRISMAT-ISMRA, Universite de Caen, UMR 6508, 6 Boulevard du Marechal Juin, F-14050 Caen Cedex, FRANCE; telephone +33 2 31 45 2608; telefax +33 2 31 95 1600; e-mail jfhamet@crismat.ismra.fr. Key words: superconductivity, thin films, multilayers.

M. Reissner and J. Lorenz, "A Comparison of Results of Different Methods for the Analysis of Flux Creep Behavior in a Melt-Textured YBCO Sample Showing Fishtail Effect." To be published in Phys. Rev. B. Institut fuer Angewandte und Technische Physik, Technische Universitaet Wien, Wiedner Hauptstrasse 8-10/050, A-1040 Wien, AUSTRIA; telefax +43 1 586 8814; e-mail reissner@email.tuwien.ac.at. 74.60.Ge; 74.60.Jg.

Valery I. Rupasov, "Towards a Rigorous Theory of Superconducting Magnetic Alloys." Department of Physics, University of Toronto, Toronto, Ontario, CANADA M5S 1A7; e-mail rupasov@physics.utoronto.ca; preprint also available at cond-mat@xxx.lanl.gov (#9707026). 74.25.Ha; 74.62.Dh; 75.20.Hr.

M. Sakai, A. Odagawa, H. Adachi, and K. Setsune, "Phase-Lock Switching of Stacked Intrinsic Josephson Junctions." Submitted to the Proc. of the 6th Int. Supercond. Electronics Conf. (ISEC'97), Berlin, Germany, June 26-28, 1997. Central Research Laboratories, Matsushita Electric Industrial Co., Ltd., 3-4 Hikaridai, Seika, Soraku, Kyoto 619-02, JAPAN; A. Odagawa's telephone +81 774 98 2514; telefax +81 774 98 2585.

M.J.R. Sandim, P. A. Suzuki, S. Spagna, S. C. Tripp, R. E. Sager, and R. F. Jardim, "Increased Resistance Below the Superconducting Transition in Granular Sm1.83Ce0.17CuO4-y Compounds." To be published in Physica C (in press). Contact R. F. Jardim, Instituto de Fisica, Universidade de Sao Paulo, C.P. 66318, 05315-970 Sao Paulo, SP, BRAZIL; telephone +55 11 818-6891 or -6896; telefax +55 11 818 6984; e-mail rjardim@if.usp.br. Key words: high-Tc oxides, electrical resistance, two-fluid theory, granularity.

S. S. Saxena, F. V. Carter, R.K.W. Haselwimmer, S.J.S. Lister, F. M. Grosche, S. V. Brown, and G. G. Lonzarich, "Unconventional Normal State and Superconductivity in the Heavy Fermion CeNi2Ge2." Low Temperature Physics, Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE, UNITED KINGDOM; telephone +44 1223-337351 or -337392; telefax +44 1223-363263; e-mail sss21@cus.cam.ac.uk.

F. Schmidl, S. Wunderlich, L. Doerrer, H. Specht, J. Heinrich, K.-U. Barholz, H. Schneidewind, U. Huebner, and P. Seidel, "HTSC-dc-SQUID Gradiometer for a Nondestructive Testing System." Submitted to the Proc. of the 3rd European Conf. on Appl. Supercond. (EUCAS'97), Veldhoven, The Netherlands, June 30-July 3, 1997. Institut fuer Festkoerperphysik, Friedrich-Schiller-Universitaet Jena, Lessingstrasse 8, D-07743 Jena, GERMANY; P. Seidel's telephone +49 3641-635685 or -635681; telefax +49 3641-635681; e-mail seidel@ifk.uni-jena.de.

S. Sengupta, J. Corpus, M. Agarwal, and J. R. Gaines, Jr., "Feasibility of Manufacturing Large Domain YBCO Levitators by Using Melt Processing Techniques." Submitted to Impact of Recent Advances in Processing of Ceram. Supercond.: Proc. of 99th Annual Mtg. of the Amer. Ceram. Soc., Cincinnati, Ohio, 1997. Superconductive Components, Inc., 1145 Chesapeake Avenue, Columbus, OH 43212; telephone (614) 486-0261; telefax (614) 486-0912; e-mail scimax@aol.com.

S. Senoussi, A. Kilic, H. K. Kilic, J. C. Moore, C.R.M. Grovenor, A. J. Collien, and M. J. Cornige, "The Critical Current Denisity of Tl-1212 and 1223-Based Superconductors." To be published in Physica C (in press). Laboratoire de Physique des Solides (URA 2 associee au CNRS), Universite Paris-Sud, Bat. 510, Centre Universitaire, F-91405 Orsay Cedex, FRANCE; telephone +33 1 69 15 53 27; telefax +33 1 69 15 60 86; e-mail senoussi@physol.lps.u-psud.fr. Key words: critical current density, magnetic irreversibilities, Tl-based granular superconductors. 74.60.-w; 74.72.Fq; 74.60.Jg.

Dong Chan Shin, Yong Ki Park, Jong-Chul Park, Suk-Joong L. Kang, and Duk Yong Yoon, "Cation Disorder and Gas Phase Equilibrium in an YBa2Cu3O7-x Superconducting Thin Film." To be published in Physica C (in press). Center for Interface Science and Engineering of Materials, Korea Advanced Institute of Science and Technology, 373-1 Kusong-Dong, Yusong- Gu, Taejon 305-701, SOUTH KOREA; telephone +82 42 869 8913; telefax +82 42 869 8920; e-mail dcshin@cais.kaist.ac.kr. Key words: thin film, cation disorder, gas phase equilibrium, YBa2Cu3O7-x.

R. V. Shpanchenko, M. G. Rozova, A. M. Abakumov, E. I. Ardashnikova, M. L. Kovba, S. N. Putilin, E. V. Antipov, O. I. Lebedev, and G. Van Tendeloo, "Inducing Superconductivity and Structural Transformations by Fluorination of Reduced YBCO." To be published in Physica C (in press). Department of Chemistry, Moscow State University, 119899 Moscow, RUSSIA. Key words: YBCO, fluorination, electron microscopy.

David S. Smith, Ali Khalfi, Noureddine Ghayoub, Evelyne Cazy, S. Suasmoro, Jean-Pierre Bonnet, and Eitan Abraham, "Thermal, Self-Field, and Microstructure Effects for Critical Currents in Polycrystalline YBa2Cu3O7-d." To be published in Physica C (in press). Laboratoire de Materiaux Ceramiques et Traitements de Surface, URA CNRS 320, Ecole Nationale Superieure de Ceramique Industrielle, 47 a 73 Avenue Albert Thomas, F-87065 Limoges Cedex, FRANCE; telephone +33 55 45 2222; telefax +33 55 79 0998.

R. Subasri, R. Pankajavalli, and O. M. Sreedharan, "High Temperature Stabilities of Ternary Oxides in the Sm-Cu-O System." To be published in Physica C (in press). Contact O. M. Sreedharan, Metallurgy Division, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu 603 102, INDIA; telephone +91 4114 40202; telefax +91 4114 40360; e-mail jbq@igcar.ernet.in. Key words: high-Tc superconductors, emf, solid electrolyte, stability, Gibbs energy.

S. Takahashi, M. Tachiki, I. Kakeya, K. Kindo, T. Mochiku, and K. Kadowaki, "Josephson Plasma Excitations in High-Tc Superconductors with Finite Dimensions." To be published in Physica C. Institute for Materials Research, Tohoku University, Katahira 2-1-1, Sendai 980-77, JAPAN; telephone +81 22 227 6200; e-mail takahasi@imr.tohoku.ac.jp.

H. Tamura, T. Haga, and Y. Abe, "Characterization of Electrochemically Grown Ba1-xKxBiO3 Single Crystals by Ion Channeling Methods." To be published in Physica C (in press). Contact T. Haga, Department of Applied Physics, Hokkaido University, Sapporo 060, JAPAN; telefax +81 11 706 7129; e-mail haga@el.hines.hokudai.ac.jp. Key words: Ba1-xKxBiO3, superconductor, electrochemical growth, ion channeling.

N. H. Tea, F.A.B. Chaves, U. Klostermann, R. Giannetta, M. B. Salamon, J. W. Williams, H. H. Wang, and U. Geiser, "Vortex Penetration Depth of kappa-(ET)2Cu[N(CN)2]Br." To be published in Physica C (in press). Contact R. Giannetta, Department of Physics and The Science and Technology Center for Superconductivity, University of Illinois at Urbana-Champaign, 1110 W. Green, Urbana, IL 61801; telephone (217) 333 5882; telefax (217) 333 9819; e-mail russg@uiuc.edu. Key words: penetration depth, flux pinning, flux lattice melting, scaling, anisotropy. 74.60.Ge; 74.25.Ha; 74.70.Kn.

Y. J. Tian, S. Linzen, F. Schmidl, R. Cihar, and P. Seidel, "Large Area YBCO Films for Device Fabrication." Submitted to Supercond. Sci. & Technol.: Proc. of Supercond. Mater. Aspects--Res. & Technol. (SMART 97), Liege, Belgium, June 26-29, 1997. Institut fuer Festkoerperphysik, Friedrich-Schiller-Universitaet Jena, Lessingstrasse 8, D-07743 Jena, GERMANY; P. Seidel's telephone +49 3641-635685 or -635681; telefax +49 3641-635681; e-mail seidel@ifk.uni-jena.de.

Z. Trajanovic, R. Shreekala, M. Rajeswari, I. Takeuchi, T. Venkatesan, E. Bauer, and F. Bridges, "Dopant Incorporation and Anisotropy in In- Plane Aligned a-Axis Oriented YBa2Cu2.78Co0.22O7-d Thin Films." To be published in Physica C (in press). Center for Superconductivity Research, Department of Physics, University of Maryland, College Park, MD 20742; telephone (301) 405 7672; telefax (301) 314 9541; e-mail zt3@umail.umd.edu.

D. Vaknin, L. L. Miller, and J. L. Zarestky, "Unusual Stacking of the Square Lattice Antiferromagnetic Planes in Ca2CuO2Cl2." Submitted to Phys. Rev. B. Ames Laboratory-USDOE and Department of Physics and Astronomy, Iowa State University, Ames, IA 50011-3020; L. L. Miller's e- mail miller@ameslab.gov. 74.72.Jt; 75.25.+z; 75.50.Ee; 75.40.Cx.

Ph. Vanderbemden, Ch. Destombes, R. Cloots, and M. Ausloos, "Magnetic Flux Penetration and Creep in BSSCO-2223 Composite Ceramics." Submitted to Supercond. Sci. & Technol.: Proc. of Supercond. Mater. Aspects--Res. & Technol. (SMART 97), Liege, Belgium, June 26-29, 1997. SUPRAS, Montefiore Electricity Institute B28, University of Liege, Sart-Tilman, B-4000 Liege, BELGIUM; e-mail vanderbe@montefiore.ulg.ac.be.

T. Watanabe, T. Fujii, and A. Matsuda, "Anisotropic Resistivities of Precisely Oxygen Controlled Single-Crystal Bi2Sr2CaCu2O8+d: Systematic Study on 'Spin Gap' Effect." To be published in Phys. Rev. Lett. NTT Basic Research Laboratories, 3-1 Morinosato Wakamiya, Atsugi-shi, Kanagawa 243-01, JAPAN; telephone +81 462 40 3561; telefax +81 462 70 2364; e-mail watanabe@will.brl.ntt.co.jp. 74.25.Fy; 74.62.Dh; 74.72.Hs.

Yasuo Watanabe, Kouichi Miyake, Akihiko Endo, Kiyoshi Murata, Yuh Shiohara, and Takateru Umeda, "Improvement of Jc Properties of Sm1+xBa2- xCu3Oy Superconductors by Composition Controlled Melt Growth Processes in Air." To be published in Physica C (in press). Graduate School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113, JAPAN; telephone +81 3 3536 5711; telefax +81 3 3536 5705. Key words: Sm123 superconductor, initial composition, melt process, 211 particle size.

J. C. Wei, L. Horng, and T. J. Yang, "Magnetic Force Signal of Vortex Creation in Type-II Superconducting Thin Films." To be published in Physica C (in press). Contact L. Horng, Department of Physics, National Changhua University of Education, Changhua, 50058 Taiwan, REPUBLIC OF CHINA; telephone +886 4 723 2105, ext. 3324; telefax +886 4 721 1153; e- mail plhorng@ncue4680.ncue.edu.tw.

Roland Weidl, Steffen Brabetz, Frank Schmidl, Frank Klemm, Swen Wunderlich, and Paul Seidel, "A System for Biomagnetic Measurement (MCG) with Planar Single-Layer High-Tc dc-SQUID Gradiometers in Unshielded Environment." Submitted to the Proc. of the 3rd European Conf. on Appl. Supercond. (EUCAS'97), Veldhoven, The Netherlands, June 30-July 3, 1997. Institut fuer Festkoerperphysik, Friedrich-Schiller-Universitaet Jena, Lessingstrasse 8, D-07743 Jena, GERMANY; P. Seidel's telephone +49 3641- 635685 or -635681; telefax +49 3641-635681; e-mail seidel@ifk.uni- jena.de.

A. Wienss, G. Jakob, P. Voss-de Haan, and H. Adrian, "History Dependence of the Magnetization of Thin HTSC Films: An Explanation for Distorted SQUID Signals." To be published in Physica C (in press). Contact G. Jakob, Institut fuer Physik, Johannes-Gutenberg-Universitaet Mainz, Staudinger Weg 7, D-55099 Mainz, GERMANY; telephone +49 6131 39 4133; telefax +49 6131 39 5156; e-mail jakob@mail.uni-mainz.de. Key words: high-Tc superconductivity, thin superconducting films, critical state model, magnetization curve.

I. Wilke, G. Nakielski, J. Koetzler, K. O. Subke, C. Jaekel, F. Huening, H. G. Roskos, and H. Kurz, "Dynamic Conductivity of YBCO Thin Films from Low to Very High Frequencies." To be published in the Proc. of the 3rd European Conf. on Appl. Supercond. (EUCAS'97), Veldhoven, The Netherlands, June 30-July 3, 1997. Institut fuer Angewandte Physik, Universitaet Hamburg, Jungiusstrasse 11, D-20355 Hamburg, GERMANY; telephone +49 40 4123 2912; telefax +49 40 4123 3589; e-mail wilke@physnet.uni-hamburg.de.

N. L. Wu, Z. L. Du, Y. Y. Xue, I. A. Rusakova, D. K. Ross, L. Gao, Y. Cao, Y. Y. Sun, C. W. Chu, M. Hervieu, and B. Raveau, "Observation and Identification of a 107 K Superconducting Family in the CaBa2Ca2Cu3O9-d System." Preprint #97:076; submitted to Physica C. Contact C. W. Chu, Texas Center for Superconductivity, University of Houston, Houston, TX 77204-4792; telephone (713) 743-4514; telefax (713) 743-4513; preprints also available at e-mail preprints@www.tcs.uh.edu. Key words: superconductor, Ba2-yCa3+y-xCu3+xO9-d, structure. 74.72.Jt; 74.62.Bf; 61.66.Fn.

X. M. Xiong, Z. Q. Peng, Y. L. Zhou, Z. H. Cheng, H. B. Lu, H. S. Wang, D. F. Cui, L. Li, and G. Z. Yang, "Dependence of the Laser-Induced Voltages on the Oxygen Content in Normal State YBa2Cu3O7-d Films." To be published in Physica C (in press). Laboratory of Optical Physics, Institute of Physics and Center for Condensed Matter Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100080, PEOPLE'S REPUBLIC OF CHINA; telephone +86 10 255 9131; telefax +86 10 256 2605; e-mail ylzhou@aphy02.iphy.ac.cn. Key words: thermoelectric power, YBCO thin film, oxygen stoichiometry, laser-induced voltage. 73.50.Lw; 74.76.Bz.

Y. Yu, X. N. Xu, H. L. Ji, H. M. Shao, M. J. Qin, X. Jin, X. X. Yao, X. S. Rong, B. Ying, and Z. X. Zhao, "Dependence of Flux-Creep Activation Energy upon Current Density in HgBa2Ca2Cu3Oy." To be published in Physica C (in press). Department of Physics and Laboratory of Microstructure of Solid States, Nanjing University, Nanjing 210093, PEOPLE'S REPUBLIC OF CHINA; e-mail xmbao@nju.edu.cn.

X. Zhang, W. H. Lu, and C. K. Ong, "Structural Changes in HgBa2Ca2Cu3O8+d Under High Pressure." To be published in Physica C (in press). Department of Physics, National University of Singapore, Low Kent Ridge Road, Singapore 0511, SINGAPORE; telephone +65 772-2603 or -2604; telefax +65 777 6126.

Y. Zhao, H. Zhang, G. D. Gu, S. H. Han, G. J. Russell, and N. Koshizuka, "Correlative Motion of Vortices Near Vortex Lattice Melting Point in Bi2Sr2CaCu2O8+y Single Crystals." To be published in J. Phys. Cond. Mat. Superconductivity Research Group, University of New South Wales, Sydney 2052, AUSTRALIA; telephone +61 2 9385 5986; telefax +61 2 9385 5956; e-mail y.zhao@unsw.edu.au. 74.60.Ge; 74.40.+k; 47.52.+j.

COMING EVENTS (An * indicates a previously listed event.)

*March 12 - 13, 1998: JFCC International Workshop in Fine Ceramics '98 -- Ceramics Material Systems with Composite Structure, Nagoya, Japan. Topics include fabrication and processing; microstructure control, characterization, and design interface/interface control, characterization, and design; mechanical and functional characterization; and testing methods and nondestructive evaluation. Papers are solicited. Abstract deadline August 31, 1997. Proceedings to be published in Ceramic Transactions. Official language is English. For information, contact Noriyuki Kosuge, c/o JFCC, 2-4-1 Mutsuno, Atsuta, Nagoya 456, Japan; telephone +81 52 871-3500; telefax +81 52 871-3599.

*March 18 - 20, 1998: 6th International Symposium on Trends and Applications of Thin Films (TATF98), Regensburg, Germany. Conference is dedicated to new applications of thin films and systems, and their production and analysis. Topics include: 1) Hard, Protective, and Decorative Coatings -- processes, diagnostics/process control, innovative materials, large area and high-rate deposition; 2) Films for Microelectronics and Microsystems -- processing and diagnostics, metallization, multilayers, sensors, surface micromachining, and 3D microstructures; 3) Hot Topics -- materials and characterization, film production and equipment, film properties, micro- and nanostructures, intelligent and self-organizing systems, and bioactive and biocompatible films. For information contact H. Hoffmann, Inst. fuer Experimentelle und Angewandte Physik, Universitaet Regensburg, Universitaetsstrasse 31, D-93040 Regensburg, Germany; telephone +49 941 943 2621; telefax +49 941 943 4544; e-mail horst.hoffmann@physik.uni-regensburg.de.

*March 29 - April 3, 1998: Symposium on Applications of Spectroscopy to Superconducting Materials, 215th Spring National American Chemical Society Meeting, Dallas, Texas. Call for papers. Topics will include oral sessions of optical spectroscopies, photoexcitation spectra, other spectra, and applications. The meeting is not restricted to cuprates and may include studies of organic superconductors, fullerides, heavy fermions, and conventional materials. Proceedings to be published. Abstract deadline, September 1, 1997. Contact E. Faulques, Institut the Materiaux, LPC, 2 rue de la Houssiniere, BP 32229, F-44322 Nantes Cedex 3, France; telephone +33 2 40 373972; telefax +33 2 40 373991; e-mail faulques@cnrs-imn.fr; Web site http://www.acs.org/.

*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.

FYI (High-Tc Update takes no responsibility for want ads listed in this section.)

Position Open: Institut fuer Nukleare Festkoerperphysik, Karlsruhe, Germany, has an immediate opening for a Ph.D. fellow (three-year contract) to work on current leads based on YBCO bulk material technology. Experience in contact techniques applicable to bulk materials, high voltage/high current, and cryogenics preferred. A one- page cover letter including research plan and a one-page CV should be faxed to H. J. Bornemann +49 7247 82 4624. (Open positions are announced at the Web site http://www.infp.fzk.de/wheel/english/home.htm.)

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, #16, August 15, 1997.