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.

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Vortices

Magnetic-decoration experiments by F. Pardo (Bariloche) et al. show evidence in single-crystal NbSe2 for a transition from a smectic flux- line lattice at low vortex densities to a moving-Bragg-glass (MBG) phase at high densities. These findings, which are in accord with recent theoretical predictions, were obtained by Fourier transforming real- space decoration patterns of moving and quasistatic vortex arrays. The experiments confirm the idea that flow can induce order in the flux-line lattice.

Evidence for forced topological entanglement of line-like vortices in the liquid regime of YBa2Cu3O7-d with columnar defects has been found experimentally by D. Lopez (IBM-Yorktown) et al. By splaying the defects within a fixed plane (in-fan), the authors created a c-axis phase-coherent vortex structure which correlates with anisotropic dissipation. The high-field vortex motion is "easy" in-fan and "hard" across-fan in crystals, a signature of forced entanglement by small- angle splay. On the other hand, the high-field anisotropy is reversed in thin films, where forced entanglement is absent.

Vortex lattices in the high-temperature superconductors have been shown experimentally to undergo a first-order phase transition, which has thus far been regarded as melting from a solid to a liquid. A preprint by H. M. Carruzzo and C. C. Yu (UC-Irvine) proposes an alternative possibility of a two-step process, in which there is a first-order transition from an ordinary vortex lattice to a soft vortex solid, followed by a second first-order melting transition from the soft vortex solid to a vortex liquid. In this preprint, the authors focus on the premelting transition, induced by vacancies and interstitial vortex lines. The authors find good agreement with the experimental latent heat, magnetization jump, and transition temperature versus field for YBa2Cu3O7-d and Bi2Sr2CaCu2O8+d.

The electromagnetic pinning of vortices by voids, holes, and surface defects in anisotropic and layered superconductors has been calculated by A. Buzdin and M. Daumens (Bordeaux).

A preprint by G. E. Volovik (Helsinki and Landau Institute) theoretically describes the spectrum of electronic bound states in the vortex core. For a vortex with winding number n = 1 in the presence of disorder, the author finds that the spectrum can be split, but that the levels have equal spacings on each sub-branch of the spectrum.

A paper by J. Kolacek and P. Vasek (Prague) explains the Hall-voltage sign reversal using a model in which vortices, superconducting charge carriers, and normal-state charge carriers are regarded as three subsystems mutually connected by interactions. By solving the equations of motion, the authors obtain a new Hall-resistivity formula, which qualitatively explains the experimental data.

La Cuprates

A preprint by P. Blakeslee (MIT) et al. reports measurements of the time dependence of the current during electrochemical oxidation and reduction at fixed voltage of single crystals and ceramic samples of La2CuO4+d. The current was found to decay too rapidly and the temperature dependence was found to be too weak to be consistent with a diffusion- limited reaction. Staging peaks in neutron measurements of the single crystals, together with the electrochemical measurements and magnetization measurements, confirm that stage n = 6 (a period of 6 times the underlying c-axis lattice constant) corresponds to d = 0.055+- 0.05, the high side of the oxygen-rich - oxygen-poor miscibility gap.

Systematic low-energy neutron-scattering studies have been performed by K. Yamada (Tohoku) et al. on float-zone-grown single crystals of La2- xSrxCuO4 with x extending from zero doping (x = 0) to the overdoped, weakly superconducting regime (x = 0.25). For x beyond a critical doping value of x_c ~~ 0.05, the low-energy spin-fluctuation peak position shifts from (1/2, 1/2) to (1/2 +- d, 1/2) and (1/2, 1/2 +- d); x_c also represents the onset concentration for superconductivity. For 0.06 <= x <= 0.12, the incommensurability d follows approximately the relation d = x. However, beyond x ~~ 0.12, the incommensurability tends to saturate around d ~~ 1/8.

Hg Cuprates

Systematic studies of the synthesis and processing of bulk (Hg,Pb)Ba2Ca2Cu3O8+d [(Hg,Pb)-1223] superconductor (Tc = 132-134 K), showing that the microstructure and intergrain connectivity of samples depend strongly on heat treatment and Hg pressure during synthesis, are reported by P.V.P.S.S. Sastry et al. (Florida State). The authors found that use of CaHgO2 as the external Hg source during the reaction improves the density of the (Hg,Pb)-1223 products and produces large colonies of well-aligned superconducting grains. Magnetization measurements of the (Hg,Pb)-1223 samples showed open hysteresis loops at temperatures above 100 K.

Two related papers, one by P.V.P.S.S. Sastry et al. (Florida State) and the other by K. M. Amm et al. (Florida State), report synthesis and processing studies of (Hg,A)Ba2Ca2Cu3O8+d, where A = Bi and Pb.

RBa2Cu3O7-d

The effects of second-phase (Nd,Eu,Gd)2BaCuO5 (NEG-211) and Pt additions on the superconducting properties of (Nd,Eu,Gd)Ba2Cu3O7-d (NEG-123) composites prepared by the oxygen-controlled-melt-growth (OCMG) process have been studied by M. Muralidhar (SRL-ISTEC) et al. The authors found that the NEG-211 additions slightly decreased the critical temperature Tc and increased the critical current density Jc, particularly in the low-field region. The results also showed that pinning is enhanced if the second phase is more finely distributed.

The influence of Ag admixtures on the phase equilibria of YBa2Cu3O7-d near the liquidus surface has been investigated by U. Wiesner (Dresden) et al. at 0.21 x 10^5 Pa oxygen partial pressure using thermoanalytic methods (DTA and TG). The temperatures at which the liquid phase occurs are decreased by about 30 K in comparison with pure Y-Ba-Cu-O compositions. The peritectic decomposition of YBa2Cu3O7-d is replaced by two sequential univariant reactions in the presence of Ag: a eutectic reaction with a silver-rich liquid at 944^oC and monotectic- like reaction at 980^oC resulting in an Y-Ba-Cu-O-rich melt containing Y2BaCuO5.

Other Cuprates

Angle-resolved photoemission (ARPES) studies by C. Kim (Stanford) et al. of Sr2CuO2Cl2 at a temperature below its Neel temperature have revealed detailed momentum-dependent lineshape changes as a function of wave vector. While a sharp quasiparticle-like peak is observed near (pi/2, pi/2), broad peaks are observed near (pi, 0). Additional second- and third-neighbor hopping terms must be added to the t-J Hamiltonian to account for both the dispersion and the lineshape. The authors report that this Hamiltonian can be used to explain the measured momentum- dependent spectral function in hole-doped materials, both underdoped and overdoped, as well as in electron-doped materials.

As reported by S. Lupi et al. (Roma), reflectance measurements in different Nd1.96Ce0.04CuO4+y samples with properly selected carrier concentrations provide firm evidence of Fano antiresonances for the four transverse optical E_u phonons in the ab plane. By analyzing the Fano lineshapes and the temperature dependence of the renormalized phonon frequencies, the authors concluded that the electronic continuum interaction with the phonons is provided by a polaron band at ~0.1 eV.

Theory

The effects of interladder one-particle hopping t_[perp.] on the low- energy asymptotics of a weakly coupled Hubbard ladder system have been studied by J. Kishine and K. Yonemitsu (IMS) using a perturbative renormalization-group approach. The authors work out the temperature T vs. t_[perp.] phase diagram, showing boundaries between the spin-gap- metal (SGM) phase, the d-wave superconducting (SCd) phase, and the two- dimensional (2D) phase.

A preprint by J. J. Rodriguez-Nunez (Santa Maria) and S. Schafroth (Zurich) proposes an Ansatz for the self-energy Sigma(k,omega) having a single pole at Omega(k), with spectral weight alpha(k) and quasiparticle decay rate Gamma(k), and examines the consequences for the density of states in the two-dimensional Hubbard model at half-filling. As a function of the local interaction U, the authors find a Mott metal- insulator transition (MMIT) from a metal at small U (no gap at zero frequency) to a well-developed gap (insulator) at large U.

The two-dimensional Hubbard model has been analyzed by A. Avella (Salerno) et al. using the framework of the two-pole expansion. The authors demonstrate that several theoretical approaches, when considered at the lowest level, are all equivalent and share the property of satisfying conservation of the first four moments (n = 0, 1, 2, and 3) of the spectral weight A(k,omega).

The mechanism of pairing of holes in CuO2 planes has been studied by M. Cini and A. Balzarotti (Roma) using exact diagonalization in symmetric clusters with <=21 atoms and 4 holes in the three-band Hubbard model. By a diagrammatic expansion of the ground-state energy and the scattering amplitude, the authors also obtain spin-flip diagrams for the effective interaction, which is attractive for singlets and repulsive for triplets.

A preprint by E. Puchkaryov and K. Maki (USC) uses an analysis of impurity scattering in the Born limit (as opposed to the unitarity limit) to study the consequences of Ni substitution of Cu in CuO2 planes in hole-doped high-Tc cuprates. The authors present the model's predictions of how Ni substitutions affect the superconducting transition temperature, the zero-temperature gap, the residual (E = 0) quasiparticle density of states, the NMR Knight shift, the T-linear term in the specific heat, the superfluid density, the specific-heat jump at Tc, and the thermal conductivity.

The derivation and application of a renormalized Hamiltonian for electron-phonon interactions are described in a preprint by A. Mielke (Heidelberg). The author applies the method to calculate Tc vs. lambda, the electron-phonon coupling strength, for large values of lambda (up to ~2) and compares the results with experiment.

A preprint by T. Hotta and Y. Takada (Tokyo) reports the derivation of an asymptotically exact result for the renormalized phonon energy as a function of the on-site Coulomb repulsion U_[ee] in the half-filled Hubbard-Holstein model in the strong-coupling region at zero temperature. A related preprint by the same authors examines superconductivity in the polaron-liquid phase, which appears at the balance between Coulomb repulsion and phonon-mediated attraction.

Several features in the normal state of the cuprates have been interpreted using a pseudogap. J. Bouvier and J. Bok (Paris) assert that these results may be explained by the band structure of the CuO2 planes in the metallic region, where the band structure exhibits saddle points (Van Hove singularities).

In a preprint by A. V. Balatsky (Los Alamos), the author argues that, under certain conditions, a d_[x^2-y^2] superconductor exhibits a transition into a d_[x^2-y^2] + id_[xy] state in the presence of magnetic impurities. The transition is driven by linear coupling between the impurity magnetization and the d_[xy] component. Spontaneous violation of time-reversal symmetry and parity occurs.

The magnetic properties of the two-dimensional t-t'-U model have been investigated by A. Avella et al. (Salerno) by studying the static spin susceptibility as a function of momentum for various temperatures. The authors obtain results in qualitative agreement with experiments on La2- xSrxCuO4 and YBa2Cu3O7-d.

The correlation length of the square-lattice spin-1/2 Heisenberg antiferromagnet has been studied by B. B. Beard (Christian Brothers) et al. in the low-temperature (asymptotic-scaling) regime. The authors were able to probe correlation lengths up to xi ~~ 350,000 lattice spacings, more than three orders of magnitude larger than in any previous study. The results have direct implications for the zero- temperature behavior of spin-1/2 ladders.

Thin Films

The deposition of biaxially aligned Pr6O11 thin films by ion-beam- assisted laser deposition on mechanically polished metal-alloy substrates is reported by V. Betz et al. (Dresden). The authors suggest that, because of the small lattice mismatch (0.3%) with YBa2Cu3O7-d films, Pr6O11 could be an attractive alternative to the buffer-layer system YSZ (yttria-stabilized zirconia)/CeO2, currently under study for the fabrication of superconducting tapes with high critical current.

A preprint by X. Cui (TCSUH) et al. reports that a SrTiO3 buffer layer as thin as 6 nm is sufficient to grow highly crystalline YBa2Cu3O7-d thin films on MgO substrates. TEM studies showed that the SrTiO3 layers were strain-relieved by an array of periodic edge dislocations.

The preparation and study of c-axis-oriented YBa2Cu3O7-d thin films by metalorganic chemical vapor deposition (MOCVD) on MgO (100) substrates using liquid-state sources with and without fluorine are reported by Y. Yoshida (SRL-ISTEC) et al. The authors also studied the surface morphology of the films using atomic force microscopy (AFM).

The burn-out of superconducting YBa2Cu3O7-d thin-film bridges by large transport currents (up to densities of 2 x 10^7 A/cm^2) has been investigated by M. E. Gaevski (Oslo) et al. using both magneto-optical imaging of the flux distribution and low-temperature scanning electron microscopy of the Tc distribution. The authors found that the destruction is preceded by significant penetration of magnetic field inside a weak-pinning region.

The quality of thin, c-axis-oriented YBa2Cu3O7-d films deposited on LaAlO3, YSZ, and MgO in an rf-sputtering system using a single YBCO target in off-axis geometry has been studied by R. Krupke et al. (Tel Aviv). The authors found that after many growths using the same target, the Tc of the films degraded and holes appeared in the surface. The authors found a correlation between the appearance of holes, an Y-rich film composition, and the secondary phase Y2O3.

Junctions

A theoretical model for tunneling spectroscopy employing tight-binding band structure, d_[x^2-y^2] gap symmetry, group velocity, and tunneling directionality has been studied by Z. Yusof et al. (IIT). The authors examined the extent to which this model can duplicate the tunneling conductance obtained experimentally in Bi2Sr2CaCu2O8+d. Although most of the experimentally observed features can be explained theoretically, dip features at |eV| ~ 2Delta in the data are not found for any range of parameters in the model, indicating that these features are caused by other physical mechanisms, such as strong-coupling effects or inelastic tunneling.

A preprint by M. G. Medici (Nice) et al. reports that illuminating YBa2Cu3Ox grain-boundary Josephson junctions with visible light increases the local Josephson coupling. This change is characterized by an increase of the critical current and a large shift in the voltage position of the Fiske resonances. The effect is due to persistent photoinduced superconductivity (PPS) of the oxygen-depleted YBa2Cu3Ox barrier, similar to the PPS found in illuminated oxygen-deficient YBa2Cu3Ox thin films.

For microelectronic applications of Josephson junctions made from high- temperature superconductors, a reliable process technology with low spread in the junction parameters and high yield is required. K.-O. Subke et al. (Hamburg) propose that such a technology can be based on YBa2Cu3O7 ramp-edge junctions using PrBa2Cu3O7 as the barrier material and SrTiO3 for insulating layers.

Applications

A new process for making YBa2Cu3O7-d high-temperature superconducting multilayer circuits is reported in a paper by H. Q. Li (NIST-Boulder) et al. The process can provide both shallow edges for crossovers and steep edges to define small features. The authors prepared and tested stacked Josephson junctions on SrTiO3 bicrystal substrates. A multilayer low- inductance dc SQUID fabricated using this process was found to show large voltage modulation.

A preprint by J. C. Booth (NIST-Boulder) reports measurements of third- harmonic generation of coplanar waveguide (CPW) transmission lines to explore the behavior of nonlinearities in microwave devices fabricated from high-Tc superconductors. The authors studied the effect of varying the CPW geometry, including center line width, line length, and YBa2Cu3O7-d film thickness, upon the nonlinearity of the transmission- line circuit as measured by the third-order intercept.

Three types of integrated magnetometers intended for biomagnetic multichannel systems have been investigated by S. Krey (Hamburg) et al.: the Ketchen-type magnetometer, the multiloop magnetometer, and the magnetometer with integrated multiloop pickup coil (IMPUC). The authors compare the three types with respect to their effective flux-collecting area, inductance, and noise performance.

Isothermal melt processing has been used by T. G. Holesinger et al. (Los Alamos) to partially texture bulk samples of Bi2Sr2CaCu2O8+d (Bi-2212) intended for use in current-lead applications. The authors note that anisotropic growth of Bi-2212 occurs from the partial melt in an oxygen gradient; the orientational preference is for the c axis of the Bi-2212 grains to align themselves perpendicular to the oxygen gradient. While the one-dimensional nature of the oxygen gradient does not result in uniaxial texture, the authors found that incorporation of a set of silver plates aligned parallel to the oxygen gradient can provide the second texturing mechanism needed to improve grain-to-grain alignment and start the development of uniaxial texture within bulk Bi-2212 bars. The authors investigated the resulting texture by measuring the critical-current anisotropy in applied magnetic fields and comparing with previously published results on Bi-2212 thick films. At liquid- nitrogen temperatures, the presence of partial texture in the bulk Bi- 2212 bars was found to increase the performance in applied fields by a factor of two relative to untextured current leads. However, the authors found that the grain-orientation spread in a bulk-textured Bi- 2212 bar was significantly larger than in a 50 micrometers thick Bi-2212 film.

Other Activities

The normal-state Hall coefficient R_H and in-plane resistivity rho_[ab] have been measured by Y. Ando (Bell Labs and CRIEPI) et al. in La-doped Bi2Sr2CuO6 (Bi-2201, Tc ~~ 13 K) single crystals and La2-xSrxCuO4 thin films by suppressing superconductivity with 61 T pulsed magnetic fields. In contrast to data above Tc, the R_H below ~10 K shows little temperature dependence in all the samples measured, irrespective of whether rho_[ab] exhibits insulating or metallic behavior. Thus, whatever physical mechanism gives rise to insulating behavior in the low-temperature normal state, it leaves the Hall conductivity relatively unchanged.

A preprint by B. Andrzejewski and J. Stankowski (Poznan) reports the use of magnetically modulated microwave absorption to measure the intergranular and intragranular critical fields, H_[c1J] and H_[c1G], and the intergranular critical current density J_[cJ] in ceramic samples of YBa2Cu3O7-d.

The information to be gained from magneto-thermoelectric studies of high-temperature superconductors (electrical resistivity, thermoelectric power, electrothermal conductivity, Nernst effect, transport entropy, Hall effect) is discussed in a preprint by M. Pekala (Warsaw) and M. Ausloos (Liege).

According to a preprint by H. A. Blackstead (Notre Dame) and J. D. Dow (Arizona State), the reason for the superconductivity or lack thereof in RBa2Cu2NbO8, RBa2Cu3O7, RBa2Cu4O8, R2-xCexCuO4, and R2-zCezSr2Cu2NbO10 (R = rare earth) is that superconductivity is localized in the charge reservoir and not in the CuO2 planes.

Overviews

A review by J. A. Wilson and A. Zahrir (Bristol) of the two-subsystem, negative-U interpretation of high-temperature superconductivity in the mixed-valent, square-planar cuprate metals just appeared in Rep. Prog. Phys. The authors included an addendum that covers publications through 1996 (272 refs.).

The evolution of magnetic, transport, and optical properties with increasing carrier density in the CuO2 layers has been reviewed by M. A. Kastner (MIT) et al. The authors discuss the results of a wide variety of experiments on materials such as La2CuO4 and Nd2CuO4, containing weakly coupled CuO2 layers. These materials are antiferromagnetic insulators with very large Heisenberg exchange energies, which become high-temperature superconductors when charge carriers are added to the CuO2 layers (163 refs.).

Multiterminal transport experiments probing the superconducting phase coherence in the direction of the applied magnetic field in the solid and liquid vortex phases of YBa2Cu3O7-d (YBCO) have been reviewed by E. F. Righi et al. (Bariloche). The authors give a detailed account of recent investigations of vortex velocity correlations and the longitudinal resistivity (parallel to both the applied magnetic field and the c crystallographic axis) when the static disorder and the anisotropy are varied in the YBCO system (82 refs.).

A review of the melt-texturing and modeling of YBa2Cu3O7-d/Y2BaCuO5 (123/211) composites under isothermal conditions has been prepared by N. Vandewalle (Liege). The author reports that a multigrain growth model gives a good account of the development of 123/211 composites (50 refs.).

Recent developments in the powder-in-tube fabrication of (Bi,Pb)2Sr2Ca2Cu3O10+d [(Bi,Pb)-2223] are reviewed by U. Balachandran (Argonne) et al. The authors discuss and assess the identification of the high-current-transport regions of the superconductor core, optimization of conductor design and processing to take advantage of these high-current regions, optimization of superconductor powders and heat treatments, and incorporation of flux-pinning defects into the superconducting grains (46 refs.).

A preprint by M. Schilling (Hamburg) presents a brief survey of the current status of integrated, thin-film YBa2Cu3O7-d SQUID magnetometers optimized for use at 77 K. The author describes several magnetometer concepts and discusses noise sources (22 refs.).

A brief review of the general strategy behind the SO(5) theory of high- Tc superconductivity has been prepared by S.-C. Zhang (Stanford). The author reviews progress in the direction of exact SO(5) models, numerical exact diagonalization, and possible experimental tests. The author also addresses criticisms recently raised against the SO(5) theory and points out directions for future exploration (20 refs.).

Information about the properties of YBCO films obtained by far-infrared spectroscopy has been reviewed by X. Gerbaux (Nancy) et al. The authors find that many of the results are in accord with previous microwave experiments, but that some of them are still puzzling (18 refs.).

A paper by C. W. Chu (TCSUH) briefly summarizes the present state of high-temperature superconductivity research and development, assesses the prospects for still higher transition temperatures, and outlines the challenges the field is currently facing. The author foresees a new era of materials engineering for the fabrication of perovskite and related oxide superlattices (12 refs.).

Ph.D. Thesis

Self-field ac-loss measurements on superconducting Bi-2223/Ag tapes and single-phase prototype cable conductors have been investigated in the Ph.D. thesis of S. A. Awan (Newcastle upon Tyne). The author derived several new models for the nonlinear current-dependent inductance and harmonic components and compared these with measurements. For prototype superconducting cables, the author found that numerous factors had to be taken into account for accurate and reproducible loss measurements, including voltage-contact position, I_c distribution, and contact resistance between the tapes and the current contacts (108 refs.).

Contributed by John R. Clem

Contents: Preprints begin on page 6; Coming Events begin on page 11; Resouces begin on page 12; FYI is on page 13; and an a Donor Form is available on the last page of the newsletter.

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.

V. L. Aksenov and V. V. Kabanov, "Electron-Phonon Interaction and Raman Linewidth in Superconducting Fullerides." To be published in Phys. Rev. B. Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, 141980 Dubna, RUSSIA; V. V. Kabanov's e-mail viktor.kabanov@ijs.si; preprint also available at cond-mat@xxx.lanl.gov (#9709179). 79.60.Bm; 63.20.-e; 71.38.+i.

K. M. Amm, P.V.P.S.S. Sastry, D. C. Knoll, and J. Schwartz, "The Influence of Metallic Interfaces on the Properties of Bulk (Hg,A)Ba2Ca2Cu3Ox (A=Pb,Bi) Superconductors." Submitted to Adv. Cryo. Eng. National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310; telephone (850) 644-1447; telefax (850) 644-0867; e-mail pamidi@magnet.fsu.edu.

Yoichi Ando, G. S. Boebinger, A. Passner, N. L. Wang, C. Geibel, F. Steglich, I. E. Trofimov, and F. F. Balakirev, "Normal-State Hall Effect and the Insulating Resistivity of High-Tc Cuprates at Low Temperatures." Submitted to Phys. Rev. B. Bell Laboratories, Lucent Technologies, 700 Mountain Avenue, Murray Hill, NJ 07974. 74.25.Fy; 74.20.Mn; 74.72.Hs; 71.10.Hf.

Bartlomiej Andrzejewski and Jan Stankowski, "Investigating of the Magnetic Flux Trapping in HTS by Means of MMMA." Presented at the VII Nat. Symp. on Supercond., Miedzyzdroje, Poland, Sept. 1-3, 1997; to be published in Molecular Phys. Reports. Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, PL-60179 Poznan, POLAND; telephone +48 61 612 300; telefax +48 61 684 524; e-mail and@ifmpan.poznan.pl.

A. Avella, F. Mancini, D. Villani, L. Siurakshina, and V. Yu. Yushankhai, "The Hubbard Model in the Two-Pole Approximation." Contact F. Mancini, Dipartimento di Scienze Fisiche "E.R. Caianiello," Unita INFM di Salerno, Universita degli Studi di Salerno, I-84081 Baronissi (SA), ITALY; e-mail mancini@vaxsa.csied.unisa.it; preprint also available at cond-mat@xxx.lanl.gov (#9708009).

Adolfo Avella, Ferdinando Mancini, and Dario Villani, "Incommensurate Spin Fluctuations in the Two-Dimensional t-t'-U Model." Submitted to Phys. Lett. A. Dipartimento di Scienze Fisiche "E.R. Caianiello," Unita INFM di Salerno, Universita degli Studi di Salerno, I-84081 Baronissi (SA), ITALY; e-mail aveado@vaxsa.csied.unisa.it; preprint also available at cond-mat@xxx.lanl.gov (#9707266). 74.72.-h; 75.10.-b; 71.10.Fd.

Shakil Ahmed Awan, "Self-Field ac Losses in High-Tc Superconducting BSCCO-2223/Ag Tapes and Prototype Conductors." Submitted as a Ph.D. thesis (University of Newcastle upon Tyne). National Physical Laboratory, Teddington, Middlesex, TW11 0LW, UNITED KINGDOM; telephone +44 181 977 3222; telefax +44 181 943 2155; e-mail s.a.awan@ncl.ac.uk.

U. Balachandran, A. N. Iyer, K. C. Goretta, and P. Haldar, "Processing and Fabrication of High-Tc Superconductors for Electric Power Applications." Submitted to the Proc. of the 4th Int. Union of Mater. Res. Soc. Int. Conf. in Asia (IUMRS-ICA), Chiba, Japan, Sept. 16-18, 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.

A. V. Balatsky, "Spontaneous Time Reversal and Parity Breaking in a d_[x^2-y^2]-Wave Superconductor with Magnetic Impurities." To be published in J. Phys. Chem. Solids. Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545; e-mail avb@groa,lanl.gov; preprint also available at cond-mat@xxx.lanl.gov (#9709287). 74.25.Bt; 74.20.De; 74.62.Dh.

B. B. Beard, R. J. Birgeneau, M. Greven, and U.-J. Wiese, "The Square- Lattice Heisenberg Antiferromagnet at Very Large Correlation Lengths." Submitted to Phys. Rev. Lett. Department of Physics and Mechanical Engineering, Christian Brothers University, Memphis, TN 38104; R. J. Birgeneau's telefax (617) 253-8901; e-mail robertjb@mit.edu; preprint also available at cond-mat@xxx.lanl.gov (#9709110). 75.10.Jm; 02.70.Lq; 31.15.Kb; 71.10.Fd.

V. Betz, B. Holzapfel, D. Raouser, and L. Schultz, "In-Plane Aligned Pr6O11 Buffer Layers by Ion-Beam Assisted Pulsed Laser Deposition on Metal Substrates." To be published in Appl. Phys. Lett. Institut fuer Festkoerper- und Werkstofforschung Dresden, Helmholtzstr. 20, D-01069 Dresden, GERMANY; telephone +49 351 4659 206; telefax +49 351 4658 541; e-mail betz@ifw-dresden.de.

Howard A. Blackstead and John D. Dow, "Dependence of High-Temperature Superconductivity on Rare-Earth Ions." Manuscript #JR-9747; to be published in J. Appl. Phys. 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. Key words: superconductivity, rare earths. 74.20.Fg.

P. Blakeslee, R. J. Birgeneau, F. C. Chou, R. Christianson, M. A. Kastner, Y. S. Lee, and B. O. Wells, "Electrochemistry and Staging in La2CuO4+d." Submitted to Phys. Rev. B. Center for Material Science and Engineering and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139; R. J. Birgeneau's telefax (617) 253- 8901; e-mail robertjb@mit.edu. 74.72.-h; 66.30.-h; 82.45.+z.

James C. Booth, J. A. Beall, R. H. Ono, F.J.B. Stork, D. A. Rudman, and L. R. Vale, "Third-Order Harmonic Generation in High-Temperature Superconducting Coplanar Waveguides at Microwave Frequencies." Submitted to Appl. Supercond: Proc. of the 6th Int. Supercond. Electronics Conf. (ISEC'97), Berlin, Germany, June 26-28, 1997. National Institute of Standards and Technology, Division 814.03, 325 Broadway, Boulder, CO 80303; telephone (303) 497-7900; telefax (303) 497-3042; e-mail booth@boulder.nist.gov.

J. Bouvier and J. Bok, "Van Hove Singularity and 'Pseudo-Gap' in HTSC." Submitted to J. Supercond. Laboratoire de Physique du Solide, UPR 5 CNRS ESPCI, 10 rue Vauquelin, F-75231 Paris Cedex 05, FRANCE; telephone +33 1 40 79 4451; telefax +33 1 40 79 4425; e-mail jacqueline.bouvier@espci.fr.

J. Brunen, T. Strach, J. Zegenhagen, and M. Cardona, "Growth of (110)- Oriented Epitaxial RBa2Cu3O7-d Thin Films and Characterization with Raman Spectroscopy." To be published in Physica C (in press). Max- Planck-Institut fuer Festkoerperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, GERMANY; telephone +49 711 689 1728; telefax +49 711 689 1010; e-mail johannes@cardix.mpi-stuttgart.mpg.de. Key words: Raman scattering, phonon spectrum, thin film, coherence length, multilayers. 68.55.Jk; 74.76.Bz; 78.30.Er; 81.15.Fg.

A. Buzdin and M. Daumens, "Electromagnetic Pinning of Vortices on Different Types of Defects." Submitted to Physica C. Centre de Physique Theorique et Modelisation, Universite Bordeaux I, Rue du Solarium, F-33174 Gradignan Cedex, FRANCE; telefax +33 5 5689 8759; e- mail buzdin@bortibm1.in2p3.fr. 74.60.Ec; 74.80.Dm.

Herve M. Carruzzo and Clare C. Yu, "First Order Premelting Transition of Vortex Lattices." To be published in Phil. Mag. B. Department of Physics and Astronomy, University of California at Irvine, Irvine, CA 92697; Clare Yu's e-mail cyu@moses.ps.uci.edu; preprint also available at cond-mat@xxx.lanl.gov (#9705092).

J. W. Chen, J. C. Wang, and Y. F. Chen, "Study of Dielectric Relaxation Behavior in Nd2CuO4." To be published in Physica C (in press). Department of Physics, National Taiwan University, Taipei, Taiwan, REPUBLIC OF CHINA; telephone +886 2 362 6937; telefax +886 2 363 9984. 77.22.Gm; 77.84.Bw.

C. W. Chu, "Oxides for High-Temperature Superconductivity and Beyond." Preprint #97:104; submitted to the Proc. of the Symp. on Prospects of Basic Science in the 21st Century, Beijing, People's Republic of China, June 2-3, 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.

Michele Cini and Adalberto Balzarotti, "Cluster Approach to the Three- Band Hubbard Model of the Cu-O Plane: Superconducting Pairs." To be published in Phys. Rev. B. Dipartimento di Fisica, Istituto Nazionale di Fisica della Materia, Universita di Roma "Tor Vergata," Via della, Ricerca Scientifica, I-00133 Rome, ITALY. 74.72.-h; 74.20.-z.

X. T. Cui, Q. Y. Chen, W. K. Chu, and Y. X. Guo, "Interfacial Strain Relief of SrTiO3-Buffered YBa2Cu3O7-d Thin Films on MgO Substrates." Preprint #97:107; 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. 61.16.-d; 61.72.Ff; 61.80.Mk; 74.72.Bk; 74.76.Bz.

A. Das, I. Zelenay, and R. Suryanarayanan, "Normal State Transport Properties of Y1-xPrxSrBaCu3O7 and Y1-xPrxSr2Cu2.8Re0.2O7." To be published in Physica C. Contact R. Suryanarayanan, Laboratoire de Chimie des Solides, Universite de Paris-Sud, Batiment 414, F-91405 Orsay Cedex, FRANCE; telefax +33 1 6915 4797; e-mail suryan@isma.isma.u- psud.fr. Key words: thermoelectric power, resistivity, Pr-f hybridization, chain oxygen disorder, heat treatment, Y(Pr)SrBaCu3O7, Y(Pr)Sr2Cu2.8Re0.2O7.

A. M. Dyugaev, Yu. N. Ovchinnikov, and P. Fulde, "Influence of Magnetic Impurities on the Heat Capacity of Nuclear Spins." Max-Planck-Institute for Physics of Complex Systems, Bayreuther Str. 40, Haus 16, D-01187 Dresden, GERMANY. 72.15.Eb.

M. E. Gaevski, T. H. Johansen, Yu. Galperin, H. Bratsberg, A. V. Bobyl, D. V. Shantsev, and S. F. Karmanenko, "Burning of High-Tc Bridges." To be published in Appl. Phys. Lett. Department of Physics, University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo, NORWAY.

Xavier Gerbaux, Armand Hadni, and M. Tazawa, "A Glimpse at Ten Years of Microwaves and IR Spectroscopy on High Temperature Superconductors." Presented at the 22nd Int. Conf. on Infrared and Millimeter Waves, Wintergreen, Va. 22958, July 20-25, 1997; submitted to Int. J. of Infrared and Millimeter Waves. Laboratoire de Cristallographie et Modelisation des Materiaux Mineraux et Biologiques, URA-CNRS, No. 809, Universite Henri-Poincare-Nancy 1, B.P. 239, F-54506 Vandoeuvre-les- Nancy Cedex, FRANCE.

G. C. Han and C. K. Ong, "Dissipation Near Tc in a Textured (Bi,Pb)2Sr2Ca2Cu3Oy Silver-Clad Tape." To be published in Phys. Rev. B. Department of Physics, National University of Singapore, 10 Lower Kent Ridge, 119260, SINGAPORE; telefax +65 777 6126; e-mail phyhangc@leonis.nus.sg. 74.60.Ge; 74.60.Jg.

P. Haug, D. Goehring, M. Vogt, A. Trautner, W. Wischert, and S. Kemmler- Sack, "Influence of Processing and Composition on the Formation of (Bi,Pb)-2223 Tapes." 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 Anorganische Chemie, Auf der Morgenstelle 18, D-72076 Tuebingen, GERMANY.

T. G. Holesinger, J. F. Bingert, J. O. Willis, V. A. Maroni, A. K. Fischer, and K. T. Wu, "The Effects of Variable Oxygen Partial Pressures During Bi-2223 Tape Processing." To be published in J. Mater. Res. (Nov. 1997). Materials Science and Technology MST-6, Los Alamos National Laboratory, MS G755, Los Alamos, NM 87545; telephone (505) 667- 3030; telefax (505) 665-3164; e-mail holesinger@lanl.gov.

T. G. Holesinger, J. O. Willis, M. C. Martinez, and J. Y. Coulter, "Texture Development in Bi2Sr2CaCu2Oy Current Leads." Submitted to Physica C. Materials Science and Technology MST-6, Los Alamos National Laboratory, MS G755, Los Alamos, NM 87545; telephone (505) 667-3030; telefax (505) 665-3164; e-mail holesinger@lanl.gov.

Terry G. Holesinger, W. Larry Hults, James L. Smith, Weiming Dai, and Kenneth R. Marken, "Isothermal Melt Processing of Bi-2212 Wires and Tapes." To be published in Impact of Recent Adv. in Synthesis and Processing of Ceram. Supercond.: Proc. of the Annual Mtg. of the Amer. Ceram. Soc., Cincinnati, Ohio, May 5-7, 1997. Materials Science and Technology MST-6, Los Alamos National Laboratory, MS G755, Los Alamos, NM 87545; telephone (505) 667-3030; telefax (505) 665-3164; e-mail holesinger@lanl.gov.

Takashi Hotta and Yasutami Takada, "Effect of Electron Correlation on Phonons in a Strongly-Coupled Electron-Phonon System." ISSN 0082-4798, preprint #3288; submitted to Phys. Rev. B. Institute for Solid State Physics, University of Tokyo, 7-22-1 Roppongi, Minato-ku, Tokyo 106, JAPAN. 71.38.+i; 71.10.Fd; 71.28.+d; 63.20.-e.

Takashi Hotta and Yasutami Takada, "Electron-Filling Dependence of the Superconducting Transition Temperature in the Polaron-Liquid Phase of an Extended Hubbard-Holstein Model." ISSN 0082-4798, preprint #3293; submitted to Phys. Rev. B. Institute for Solid State Physics, University of Tokyo, 7-22-1 Roppongi, Minato-ku, Tokyo 106, JAPAN. 74.20.Mn; 74.70.Wz; 71.38.+i; 71.10.Fd.

K. Kakimoto and Y. Shiohara, "Melt Growth Processing of RE123 Superconductive Oxides." To be published in Appl. Supercond. 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.

M. A. Kastner, R. J. Birgeneau, G. Shirane, and Y. Endoh, "The Evolution of Magnetic, Transport, and Optical Properties with Carrier Density in CuO2 Layers." Submitted to Rev. Mod. Phys. Department of Physics and Center for Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139; R. J. Birgeneau's telefax (617) 253- 8901; e-mail robertjb@mit.edu.

C. Kim, P. J. White, Z.-X. Shen, T. Tohyama, Y. Shibata, S. Maekawa, B. O. Wells, Y. J. Kim, R. J. Birgeneau, and M. A. Kastner, "Systematics of the ARPES Spectral Function of Cuprates: Insulator, Hole- and Electron- Doped Superconductors." Department of Applied Physics and Stanford Synchrotron Radiation Laboratory, Stanford University, Stanford, CA 94305; R. J. Birgeneau's telefax (617) 253-8901; e-mail robertjb@mit.edu. 71.27.+a; 78.20.Bh; 79.60.Bm; 79.60.-i.

Jun-ichiro Kishine and Kenji Yonemitsu, "Spin Gap and Superconductivity in Weakly Coupled Ladders: Interladder One-Particle vs. Two-Particle Crossover." Submitted to J. Phys. Soc. Jpn. Department of Theoretical Studies, Institute for Molecular Science, Okazaki 444, JAPAN; e-mail kishine@ims.ac.jp; preprint also available at cond-mat@xxx.lanl.gov (#9709216). Key words: doped Hubbard ladders, interladder coupling, one-particle crossover, two-particle crossover, d-wave superconductivity, perturbative renormalization-group.

Jan Kolacek and Petr Vasek, "Hall Voltage Sign Reversal in Type II Superconductors." Submitted to Phys. Rev. B. Institute of Physics, ASCR, Cukrovarnicka 10, 16253 Prague 6, CZECH REPUBLIC; telephone +42 2 243 11137; telefax +42 2 312 3184; e-mail kolacek@fzu.cz. 74.60.Ge; 74.25.Fy.

S. Krey, K.-O. Subke, D. Reimer, M. Schilling, R. Scharnweber, and B. David, "Integrated YBa2Cu3O7 Magnetometers for Biomagnetic Applications." Submitted to Appl. Supercond: Proc. of the 6th Int. Supercond. Electronics Conf. (ISEC'97), Berlin, Germany, June 26-28, 1997. Institut fuer Angewandte Physik und Zentrum fuer Mikrostrukturforschung, Universitaet Hamburg, Jungiusstrasse 11, D-20355 Hamburg, GERMANY; e-mail krey@physnet.uni-hamburg.de; M. Schilling's telephone +49 40 4123 3629; telefax +49 40 4123 4368.

S. Kruchinin and A. Yaremko, "Interlayer Hybridization and Optical Reflection Spectra of Bismuth-Containing HTSC Crystals." Presented at the Third Joint ISTEC/MRS Int. Workshop on Supercond., Big Island, Hawaii, June 15-18, 1997. Bogolyubov Institute for Theoretical Physics, Ukrainian National Academy of Sciences, Kiev 252143, UKRAINE.

S. P. Kruchinin, A. M. Yaremko, and E. V. Mozdor, "Many Band Effects in Cuprate Superconductors." To be published in Mod. Phys. Lett. B. Bogolyubov Institute for Theoretical Physics, Ukrainian National Academy of Sciences, Kiev 252143, UKRAINE. 74.20.Mn; 76.60.-k.

R. Krupke, Z. Barkay, and G. Deutscher, "On the Origin of Hole Formation in YBCO Films." To be published in Physica C (in press). School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, 69978 Tel Aviv, ISRAEL; telephone +972 3 642 8286; telefax +972 3 640 2979; e-mail krupke@post.tau.ac.il. Key words: thin films, sputter deposition, defect structures.

H. G. Lee, A. P. Litvinchuk, M. V. Abrashev, M. N. Iliev, S. H. Xu, and C. W. Chu, "Raman Spectroscopy of YSr2Cu3O7+d." Preprint #97:098; submitted to the Proc. of the Conf. on Spectroscopies in Novel Supercond. (SNS '97), Cape Cod, Mass., Sept. 14-18, 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.

H. Q. Li, R. H. Ono, D. A. Rudman, L. R. Vale, and S. H. Liou, "Multilayer Processing of High-Tc Films and Stacked Bicrystal Josephson Junctions." Submitted to Appl. Supercond: Proc. of the 6th Int. Supercond. Electronics Conf. (ISEC'97), Berlin, Germany, June 26-28, 1997. Contact R. H. Ono, Division 814.03, National Institute of Standards and Technology, 325 Broadway, Boulder, CO 80303; telephone (303) 497-3762; telefax (303) 497-3042; e-mail ono@boulder.nist.gov.

A. P. Litvinchuk, L. Boerjesson, C. Thomsen, and P. Berastegui, "Optical Spectroscopic Study of PrBa2Cu4O8." Preprint #97:103, submitted to the Proc. of the 1997 Conf. on Spectroscopies in Novel Supercond. (SNS'97), Falmouth, Mass., Sept. 14-18, 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.

Wai Lo, Charles D. Dewhurst, David A. Cardwell, Philippe Vanderbemden, Richard A. Doyle, and Doug M. Astill, "Growth Features and Intergranular Connectivity of Melt Processed YBCO." To be published in Appl. Supercond. IRC in Superconductivity, University of Cambridge, Madingley Road, Cambridge CB3 0HE, UNITED KINGDOM; David A. Cardwell's telephone +44 1223 337050; telefax +44 1223 337074.

D. Lopez, L. Krusin-Elbaum, H. Safar, V. M. Vinokur, A. D. Marwick, J. Z. Sun, and C. Feild, "Forced Entanglement vs. Anisotropic Dissipation in a Vortex Line Liquid." Submitted to Phys. Rev. Lett. IBM Thomas J. Watson Research Center, P.O. Box 218, Yorktown Heights, NY 10598.

P. Lundqvist, P. Grahn, Oe. Rapp, and I. Bryntse, "Charge Neutral Dopings, and Doping with Holes and Electrons in REBa2Cu3O7-d (RE=Y,Sm)." To be published in Physica C (in press). Contact Oe. Rapp, Solid State Physics Department, Kungliga Tekniska Hoegskolan, S-100 44 Stockholm, SWEDEN; telephone +46 8790 7304; telefax +46 8790 6952; e-mail rapp@ftf.kth.se. Key words: substitution effects, hole concentration, electrical resistivity.

S. Lupi, M. Capizzi, P. Calvani, B. Ruzicka, P. Maselli, P. Dore, and A. Paolone, "Fano Effect in the a-b Plane of Nd1.96Ce0.04CuO4+y: Evidence of Phonon Interaction with a Polaronic Background." Submitted to Phys. Rev. B. Contact P. Calvani, Dipartimento di Fisica, Universita di Roma "La Sapienza," P. le Aldo Moro 2, I-00185 Rome, ITALY; telephone +39 6 49913493; telefax +39 6 4463158; e-mail calvani@caspur.it; preprint also available at cond-mat@xxx.lanl.gov (#9707211). 72.10.Di; 78.20.Ci.

P. J. McGinn, T. Meignan, S. Yeung, and A. Banerjee, "Improved Flux Pinning in Melt Textured YBa2Cu3O7-d Through Chemical Additions." To be published in Appl. Supercond. Department of Chemical Engineering, University of Notre Dame, Notre Dame, IN 46556; telephone (219) 631- 5580; telefax (219) 631-8366.

M. G. Medici, J. Elly, M. Razani, A. Gilabert, F. Schmidl, P. Seidel, A. Hoffmann, and Ivan K. Schuller, "Effect of Photodoping on the Fiske Resonances of YBa2Cu3Ox Grain Boundary Josephson Junctions." Submitted to J. Supercond. Contact A. Hoffmann, Department of Physics 0350, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0350; e-mail hoffmann@ucsd.edu. Key words: high-Tc superconductors, photoconductivity, Josephson effects. 73.50.Pz; 74.72.Bk; 85.25.Cp.

Andreas Mielke, "Calculating Critical Temperatures of Superconductivity from a Renormalized Hamiltonian." To be published in Europhys. Lett. Institut fuer Theoretische Physik, Ruprecht-Karls-Universitaet, Philosophenweg 19, D-69120 Heidelberg, GERMANY; e-mail mielke@pooh.tphys.uni-heidelberg.de; preprint also available at cond- mat@xxx.lanl.gov (#9709175). 74.20.Fg; 11.10.Gh; 71.38.+i.

M. Muralidhar, T. Saitoh, K. Segawa, and M. Murakami, "Effects of Second Phase and Platinum Additions on the Microstructure and the Critical Current Density of OCMG Processed (Nd-Eu-Gd)-Ba-Cu-O." To be published in Appl. Supercond. Superconductivity Research Laboratory, International Superconductivity Technology Center (ISTEC), 3-35-2 Iioka- Shinden, Morioka, Iwate 020, JAPAN; telephone +81 19 635-9015 or -9016; telefax +81 19 635-9017; e-mail miryala@istec.or.jp. Key words: melt process, (Nd, Eu, Gd)-Ba-Cu-O, second phase, Pt, microstructure, critical current density.

F. Pardo, F. de la Cruz, P. L. Gammel, E. Bucher, and D. J. Bishop, "Real Space Images of Flowing Vortex Lattices and the Observation of Smectic and Moving Bragg Glass Phases." Submitted to Nature. Lucent Technologies, 2d-209, 700 Mountain Avenue, Murray Hill, NJ 07974; e-mail pardo@physics.lucent.com.

M. Pekala and M. Ausloos, "Magneto-Thermoelectric Studies of High Temperature Superconductors." Presented at the 16th Int. Conf. on Thermoelectrics (ICT'97), Dresden, Germany, Aug. 26-29, 1997. Department of Chemistry, Warsaw University, Al. Zwirki i Wigury 101, PL- 02-089 Warsaw, POLAND; telephone +48 22 220211; telefax +48 22 230123; e-mail pekala@chem.uw.edu.pl.

Evgenii Puchkaryov and Kazumi Maki, "Impurity Scattering in d-Wave Superconductivity: Unitarity Limit Versus Born Limit." Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089-0484. 74.72.-h; 74.25.Bt; 74.25.Fy.

S. Ramanathan, M. K. Mironova, and K. Ravi-Chandar, "How Do Bi-Sr-Ca-Cu- O Whiskers Grow?" Preprint #97:102; submitted to J. Mater. Res. 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.

Esteban F. Righi, Santiago A. Grigera, Gladys Nieva, and Francisco de la Cruz, "Vortex Phase Coherence Along the c Axis in YBa2Cu3O7-d." To be published in Supercond. Rev. Centro Atomico Bariloche, 8400 San Carlos de Bariloche, ARGENTINA; preprint also available at Web site http://cabbat1.cnea.edu.ar/~grigera/.

J. J. Rodriguez-Nunez and S. Schafroth, "Metal-Insulator Transition in the Two-Dimensional Hubbard Model at Half-Filling with Lifetime Effects Within the Moment Approach." Departamento de Fisica-CCNE, Universidade Federal de Santa Maria, CAMOBI, 97105 - 900 Santa Maria RS, BRAZIL; e- mail jjrn@mfis.ccne.ufsm.br; preprint also available at cond- mat@xxx.lanl.gov (#9709080). 74.20.Fg; 74.20.-z; 74.60.-w; 74.72.-h.

P.V.P.S.S. Sastry, K. M. Amm, D. C. Knoll, S. C. Peterson, and J. Schwartz, "Synthesis and Processing of Doped Hg1Ba2Ca2Cu3Oy Superconductors." Submitted to Adv. Cryo. Eng. National High Magnetic Field Laboratory, Florida State University, 1800 E. Paul Dirac Dr., Tallahassee, FL 32310; telephone (850) 644-1447; telefax (850) 644-0867; e-mail pamidi@magnet.fsu.edu.

P.V.P.S.S. Sastry, K. M. Amm, D. C. Knoll, S. C. Peterson, and J. Schwartz, "Synthesis and Processing of (HgPb)1Ba2Ca2Cu3Oy Superconductors." Submitted to Physica C. National High Magnetic Field Laboratory, Florida State University, 1800 E. Paul Dirac Dr., Tallahassee, FL 32310; telephone (850) 644-1447; telefax (850) 644-0867; e-mail pamidi@magnet.fsu.edu. Key words: (HgPb)Ba2Ca2Cu3Oy, superconductor, Pb-doping, CaHgO2 source, magnetization.

M. Schilling, "Integrated HTS dc-SQUID Magnetometers." Submitted to Appl. Supercond: Proc. of the 6th Int. Supercond. Electronics Conf. (ISEC'97), Berlin, Germany, June 26-28, 1997. Institut fuer Angewandte Physik und Zentrum fuer Mikrostrukturforschung, Universitaet Hamburg, Jungiusstrasse 11, D-20355 Hamburg, GERMANY; telephone +49 40 4123 3629; telefax +49 40 4123 4368; e-mail schilling@physnet.uni-hamburg.de.

K.-O. Subke, S. Krey, H. Burkhardt, D. Reimer, and M. Schilling, "Process Optimization for High Yield of YBa2Cu3O7 Ramp-Edge Josephson Junctions with PrBa2Cu3O7 Barriers." Submitted to Appl. Supercond: Proc. of the 6th Int. Supercond. Electronics Conf. (ISEC'97), Berlin, Germany, June 26-28, 1997. Institut fuer Angewandte Physik und Zentrum fuer Mikrostrukturforschung, Universitaet Hamburg, Jungiusstrasse 11, D- 20355 Hamburg, GERMANY; M. Schilling's telephone +49 40 4123 3629; telefax +49 40 4123 4368; e-mail schilling@physnet.uni-hamburg.de.

N. Vandewalle, "The Isothermal Melt-Texturing of Bulk YBa2Cu3O7-x Ceramics: From Cooking to Modelling." To be published in Supercond. Sci. & Technol.: Proc. of Supercond. Mater. Aspects--Res. & Technol. (SMART 97), Liege, Belgium, June 26-29, 1997. 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.

N. V. Vo, J. O. Willis, D. E. Peterson, H. K. Liu, and S. X. Dou, "Optimization on Processing Parameters for Bi(Pb)-2223 Superconducting Tapes." Preprint #LA-UR-97-3283; to be published in Physica C. Superconductivity Technology Center, Los Alamos National Laboratory, MS G755, Los Alamos, NM 87545; telephone (505) 665-6859; telefax (505) 665- 3164; e-mail nvv@lanl.gov.

A. F. Volkov, K. E. Nagaev, and R. Seviour, "Fluctuation Conductivity in Mesoscopic Superconductor-Normal Metal Contacts." School of Physics and Chemistry, Lancaster University, Lancaster LA1 4YB, UNITED KINGDOM; R. Seviour's telephone +44 1524 65201; telefax +44 1524 844037; e-mail seviour@unix.lancs.ac.uk; preprint also available at cond- mat@xxx.lanl.gov (#9709134). 72.10.Bg; 73.40.Gk; 74.50.+r.

G. E. Volovik, "Fermions in the Vortex Core as Edge States." Low Temperature Laboratory, Helsinki University of Technology, P.O. Box 2200, FIN-02015 HUT, FINLAND; e-mail volovik@boojum.hut.fi; preprint also available at cond-mat@xxx.lanl.gov (#9709159).

U. Wiesner, G. Krabbes, M. Ueltzen, C. Magerkurth, J. Plewa, and H. Altenburg, "The Influence of Ag on Univariant Reactions and the Oxygen Content of the Eutectic Melt in the Y-Ba-Cu-(Ag)-O System." To be published in Physica C. Institut fuer Festkoerper- und Werkstofforschung Dresden e.V., Postfach 270016, D-01171 Dresden, GERMANY; G. Krabbes' telephone +49 351 2582 395; telefax +49 351 2582 314.

J. A. Wilson and A. Zahrir, "High-Tc: A Negative-U Interpretation of Cuprate Superconductivity, Incorporating Questions of Crossover, Micro- Inhomogeneity and a Compound Order Parameter." To be published in Rep. Prog. Phys. H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, UNITED KINGDOM; telephone +44 117 928 8710; telefax +44 117 925 5624.

K. Yamada, C. H. Lee, K. Kurahashi, J. Wada, S. Wakimoto, S. Ueki, H. Kimura, Y. Endoh, S. Hosoya, G. Shirane, R. J. Birgeneau, M. Greven, M. A. Kastner, and Y. J. Kim, "Doping Dependence of the Spatially Modulated Dynamical Spin Correlations and the Superconducting Transition Temperature in La2-xSrxCuO4." Submitted to Phys. Rev. B. Department of Physics, Tohoku University, Aramaki Aoba, Sendai 980-77, JAPAN; R. J. Birgeneau's telefax at MIT, Cambridge, Mass. (617) 253-8901; e-mail robertjb@mit.edu. 74.72.Dn; 75.10.Jm; 75.25.+z; 75.50.Ee.

Yutaka Yoshida, Yoshiaki Ito, Yasuji Yamada, Hisashi Nagai, Yoshiaki Takai, and Izumi Hirabayashi, "Surface Morphology of YBa2Cu3O7-y Films Prepared by Metalorganic Chemical Vapor Deposition Using Liquid Sources." Preprint #N96518; to be published in Jpn. J. Appl. Phys. Superconductivity Research Laboratory, Division VIII, International Superconductivity Technology Center (ISTEC), 2-4-1 Mutsuno, Atsuta-ku, Nagoya 456, JAPAN. Key words: YBa2Cu3O7-y thin film, MOCVD, AFM, microstructure, fluorine, liquid-state source.

Z. Yusof, J. F. Zasadzinski, and L. Coffey, "Modeling of Tunneling Spectroscopy in High-Tc Superconductors, Incorporating Band Structure, Gap Symmetry, Group Velocity, and Tunneling Directionality." Submitted to Phys. Rev. B. Science and Technology Center for Superconductivity, Illinois Institute of Technology, Chicago, IL 60616; e-mail yusozik@charlie.cns.iit.edu; preprint also available at cond- mat@xxx.lanl.gov (#9709249). 74.20.-z; 74.50.+r; 74.72.-h; 74.72.Hs.

Shou-Cheng Zhang, "Recent Developments in the SO(5) Theory of High Tc Superconductivity." Presented at the 1997 Conf. on Spectroscopies in Novel Supercond. (SNS'97), Falmouth, Mass., Sept. 14-18, 1997; to be published in J. Phys. Chem. Solids. Department of Physics, Stanford University, Stanford, CA 94305; e-mail sczhang@quantum.stanford.edu; preprint also available at cond-mat@xxx.lanl.gov (#9709289).

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

Nov. 15, 1997: SQUIDs: Past, Present and Future, NIST, Boulder, Colo. One-day symposium to be held in honor of James E. Zimmerman. The symposium will look back at the origin of the SQUID, review the present state of the art, and attempt to peer into the future. Speakers include John Clarke, Bascom Deaver, Robert Kamper, Roger Koch, James Lukens, Arnold Silver, Michael Simmonds, Donald Sullivan, Ray Radebaugh, and Martin Reite. Registration deadline, October 31, 1997. Banquet will be held in the evening. For information, contact Dick Kautz, National Institute of Standards and Technology, 325 Broadway, Boulder, CO 80303; telephone (303) 497-3391; e-mail kautz@boulder.nist.gov.

*March 24 - 29, 1998: The International Workshop on High Temperature Superconductors and Novel Inorganic Materials Engineering (MSU-HTSC V), Moscow, Russia. Workshop will be the fifth in the series organized by Moscow State University since 1989. Main topics: chemistry and technology of superconducting materials and novel inorganic materials engineering. Abstract deadline, December 15, 1997. For further information, contact A. I. D'yachenko, MSU-HTSC V Secretariat, Department of Chemistry, Moscow State University, Moscow 119899, Russia; telephone +7 095 939-3490; telefax +7 095 939-4788; e-mail dyachenko@inorg.chem.msu.su.

April 13 - 18, 1998: MRS Spring Meeting, San Francisco Marriott, San Francisco, Calif. Technical symposia, tutorials, and exhibits. For information, contact MRS Headquarters, 506 Keystone Drive, Warrendale, PA 15086; telephone (412) 779-3003 or -3004; telefax (412) 779-8310; Web site http://www.mrs.org/.

*May 3 - 8, 1998: Fullerenes: Chemistry, Physics and New Directions XI, 193rd Meeting of the Electrochemical Society, Sheraton San Diego Hotel & Marina, San Diego, Calif. Papers are invited for Symposium N16 -- Fullerene-Based Superconductors. Selected papers in the program may be assigned to a poster session. Publication of a proceedings volume is planned. Specific details about the format for contributed papers for the proceedings can be obtained from the session organizers. Abstract deadline, January 2, 1998. Contact V. Buntar, Atominstitut der Oesterreichischen Universitaeten, Schuettelstr. 115, A-1020, Vienna, Austria; telephone +43 1 727-01296; telefax +43 1 728-9220; e-mail buntar@ati.ac.at or M. Nunez-Regueiro, Centre de Recherches sur les Tres Basses Temperatures, Centre National de la Recherche Scientifique, BP 166 Cedex 09, F-38042 Grenoble, France; telephone +33 7 688-7838; telefax +33 7 687-5060; e-mail nunez@labs.polycnrs-gre.fr. For general conference information, contact the Electrochemical Society, Inc., 10 South Main Street, Pennington, NJ 08534-2896; telephone (609) 737-1902; telefax (609) 737-2743; e-mail ecs@electrochem.org.

May 26 - 28, 1998: 10th International Cryocooler Conference, Monterey Conference Center, Monterey, Calif. Technical program will consist of oral and poster sessions. Invited technical topics include Stirling and pulse-tube cryocoolers, J-T and sorption cryocoolers, G-M and TEC cryocoolers, new concepts, component developments, modeling and test techniques, performance and life test data, applications and integration issues, and low-cost coolers. Oral and poster sessions. Abstract deadline, December 12, 1997. For information, contact Peter Kittel, ICC10, MS-244-10, NASA/Ames Research Center, Moffett Field, CA 94035- 1000; telephone (650) 604-4297; telefax (650) 604-1094; e-mail pkittel@mail.arc.nasa.gov.

*June 14 - 19, 1998: Ninth International Conference on Modern Materials & Technologies (CIMTEC '98): Topical Symposium VI -- Science and Engineering of HTC Superconductivity, Florence International Congress Centre, Florence, Italy. Will highlight recent research advances in high-Tc oxide, organic, and other exotic superconductors. Fundamental aspects and theory, advances in materials synthesis, processing, and properties will be featured, as well as current developments in superconducting components and devices. Session topics are broadly classified into the following groups: materials, synthesis, processing, structure, and physical chemistry; physical properties; phenomenology of the superconducting state; theory of HTC superconductivity; and applications. Oral and poster presentations. Proceedings to be published. Official language is English. Contact 9th CMTEC, Forum on New Materials, Topical Symposium VI, P.O. Box 165, I-48018 Faenza, Italy; telephone +39 546-22661 or -664143; telefax +39 546-664138 or -663362.

RESOURCES

Information

New Book: Handbook of Applied Superconductivity, edited by B. Seeber. Two-volume reference. With nearly one hundred contributions from over eighty leading researchers in academic and industrial laboratories, the volumes cover all aspects of the subject and discuss the capabilities of superconducting technologies in a wide range of application areas including electronics, magnetic imaging, power engineering, and transportation. Handbook also deals comprehensively with basic hardware such as superconducting wires, tapes and cables, and provides guidance on the supporting ancillary equipment associated with low-temperature technology such as instrumentation, cryogenics, and materials properties at low temperatures. Includes discussion of social and economic aspects and implications of the implementation of superconducting technologies. Aimed towards a wide range of scientists and engineers interested in current and potential applications of superconductivity. All contributions are full referenced and refereed. Foreword by Bednorz and Muller. Volume 1: Fundamental Theory, Basic Hardware and Low- Temperature Science and Technology -- superconducting wires, superconducting magnets, cooling technology for superconductors, instrumentation, and materials at low temperatures. Volume 2: Applications -- present applications of superconductivity, power applications of superconductivity, and superconducting electronics. Publ. Jan. 1998; 2000 pp.; price $475; ISBN 0 7503 0377 8. Contact IOP Publishing Inc., c/o AIDC, 2 Winter Sport Lane, P.O. Box 20, Williston, VT 05495-0020; telephone (800) 632-0880; telefax (802) 864-7626. Or contact Customer Services Department, IOP Publishing Ltd., Dirac House, Temple Back, Bristol BS1 6BE, United Kingdom; telephone +44 117 929 7481; telefax +44 117 929 4318; e-mail custserv@ioppublishing.co.uk.

New Book: Phase Diagrams for High-Tc Superconductors II, edited by T. A. Vanderah, R. S. Roth, and H. F. McMurdie. Contains 310 figures with approximately 450 evaluated diagrams, most of which have appeared in the literature between 1991 and 1996. Contains a substantial amount of data obtained with variable oxygen partial pressures. Diagrams mapping the occurrence of superconductivity in composition/temperature space are included. Diagrams pertinent to all of the families of high-temperature superconductors are included and are organized as follows: oxygen plus metals and/or oxides; metals plus oxides; oxides; and oxides plus others (carbonates, gases). Publ. 1997; 275 pp.; price $63 (ACerS members $51); ISBN 1-574-98-040-8. Contact The American Ceramic Society, Book Orders, P.O. Box 6136, Westerville OH 43086-6136; telefax (614) 794- 5892; Web site http://www.acers.org.

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

Position open: Postdoctoral position available for experimental studies on strongly correlated electron systems, using nonlinear optical spectroscopy to studies of subgap excitonic states in magnetic compounds and high-Tc related materials. Candidates are required to have a strong background in optical or photoelectron spectroscopy of transition metal compounds and a working knowledge of group theory of optical transitions. Two-year contract. For information, contact D. van der Marel, Laboratory of Solid State Physics, Materials Science Centre, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands; telephone +31 50 363-7229 or -4826; telefax +31 50 363- 4825.

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Please address all contributions and inquiries to: Dr. Sreeparna Mitra, A219 Physics,
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High-Tc Update, Vol. 11, #20, October 15, 1997.