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NOTA BENE:

Surface Resistance

Two papers listed in this issue describe the development and applications of scanning near-field microwave (50 MHz - 50 GHz) microscopes that operate at temperatures from 4.2 K to room temperature and image electrodynamic properties of films in both superconducting and normal states on length scales down to about 2 micrometers. S. M. Anlage et al. (Maryland) describe such a microscope and report its use to obtain images of (a) the sheet resistance of a YBa2Cu3O7-d (YBCO) thin-film wafer, (b) bulk Nb surfaces, (c) Tc of a YBa2Cu3O7-d thin film, and (d) local properties in patterned thin-film devices. A. S. Thanawalla (Maryland) et al. describe the use of an open-ended coaxial probe with a 200 micrometers inner conductor diameter, which can operate from 77 K to 200 K in the 10 MHz - 20 GHz frequency range, to image the electric-field distribution above a Tl2Ba2CaCu2O8+d (Tl-2212) microstrip resonator (resonant frequency 8.2 GHz) at 77 K, measured at several heights. The authors also describe the use of a frequency-following circuit to study the influence of the probe on the resonant frequency of the device.

The 10 GHz surface resistance has been measured by N. Bontemps et al. (Ecole Normale Superieure) in Bi2Sr2CaCu2O8+d (Bi-2212) single crystals in the 50-85 K temperature range. The measurements probed the dissipation associated with currents flowing both within the ab plane and along the c axis. Depending upon the static field orientation theta with respect to the layers, the authors were able to identify and characterize the contributions of different kinds of vortices (Josephson or pancake vortices) through their microwave absorption properties.

Measurements of the temperature and field dependence of the radio- frequency (rf) penetration depth lambda(H,T) in oriented platelets of (Bi,Pb)2Sr2Ca2Cu3O10+d [(Bi,Pb)-2223] are reported by S. Patnaik (IIT- Kanpur) et al. The authors found critical fields H_1* and H_2* at which the dynamics changes from grain-boundary-dominated to bulk-pinning- dominated and from bulk-pinning dominated to flux flow, and identified these fields as H_[c1] of the grains and the irreversibility field, respectively. The authors also used this technique to detect the trapping of magnetic flux in grain boundaries.

A preprint by M. Ausloos (Liege) presents a theoretical discussion of the intrinsic effects of a dc magnetic field B upon the real (R_s) and imaginary (X_s) parts of the microwave surface impedance of superconductors. The author presents predicted power-law dependencies of R_s and X_s upon B for s- and d-wave superconductors. Since the published data are not always in agreement with the predicted power laws, the author suggests that this indicates the presence of extrinsic effects, such as granularity and weak links.

A preprint by P. Raychaudhuri (IIT-Kharagpur) and V. V. Srinivasu (TIFR- Mumbai) reports the observation of anomalous oscillations and hysteresis in the surface resistance at 77 K in Bi-2212 bulk samples as the applied dc magnetic field increased from zero to 1000 Oe and then decreased back to zero. The authors explain the oscillations by considering the sample as a network of Josephson junctions and loops, and they attribute the observed hysteresis to flux trapping in the network.

ac Losses

Formulae for the eddy-current ac power loss and the ac hysteresis loss of z-stacks and x-arrays made of metal-superconducting strips are presented in a paper by K.-H. Mueller (CSIRO). The author examines the ac losses in self-field (transport losses) and in an applied ac magnetic field for different stacking spacings of a z-stack and different lateral spacings of an x-array. The author evaluated the losses numerically and found that at 50 Hz the eddy-current loss in a z-stack or an x-array made of YBCO/Hastelloy tapes is much smaller than the hysteresis loss, while in a z-stack or x-array made of monofilamentary Bi-2223/Ag tapes the eddy-current loss contributes significantly at small current or small magnetic field amplitudes.

Various factors influencing the ac losses in multilayer cables consisting of many superconducting tapes are considered in a preprint by A. M. Campbell (IRC-Cambridge). The author considers such factors as the cable impedance, hysteresis losses, silver losses, the effect of barriers, helical conductors, the current-transfer length, the continuum model, and the effect of the other two phases in a three-phase cable.

Vortices

The longitudinal and Hall voltages have been measured by G. D'Anna (EPFL-Lausanne) et al. in a clean twinned YBa2Cu3O7-d single crystal in the liquid and solid vortex phases. For magnetic fields tilted away from the c axis by more than about 2 degrees, a scaling law |rho_[xy]| = Arho_[xx]^[beta] with beta ~~ 1.4 was observed, which was unaffected by the vortex-lattice melting transition. For magnetic fields aligned parallel to the c axis, however, the twin-boundary correlated disorder modified the scaling law, giving beta ~~ 2. The scaling law was unaffected by the Bose-glass transition.

Magnetoresistance measurements of the effects of 9 MeV proton irradiation on a clean, untwinned single crystal of YBa2Cu3O7-d are reported by A. M. Petrean (Western Michigan and Argonne) et al. Before irradiation, the authors observed the first-order vortex-melting transition. After proton irradiation, which produces point-like disorder, the authors found evidence for a second-order vortex-glass transition. The results suggest that a sufficiently high defect density is required for the vortex-glass phase to be observed.

High-resolution specific-heat measurements along the vortex-melting line in RBa2Cu3O7-d (R = Y, Dy, and Eu) crystals are reported by M. Roulin et al. (Geneve) in magnetic fields up to 16 T parallel to the c axis. Depending upon the magnitude of the magnetic field and the quality of the crystal, the authors observed the first-order vortex-melting transition, the Bose-glass transition, or the vortex-glass transition.

Measurements of the Nernst effect (flux-flow voltage induced by a temperature gradient) in magnetic fields up to 4 T along the c axis in textured Bi-2223 have been used by M. Pekala (Warsaw) and M. Ausloos (Liege) to determine the vortex-lattice melting line B_M(T). The authors measured the Nernst voltage N vs. temperature T at different fields B, and obtained the melting line from the temperatures at which changes in the slope dN/dT occurred.

Three preprints listed in this issue report on various features of vortex flow extracted from simulations. A. P. Mehta et al. (Michigan) note that river basins as diverse as the Nile, the Amazon, and the Mississippi satisfy certain topological invariants known as Horton's laws. From analysis of the morphology and statistical properties of networks resulting from flux-gradient-driven vortex flow in superconductors containing a random distribution of pinning centers, the authors derive a phase diagram (on the plane of pinning force vs. vortex density) of different network morphologies, including one in which Horton's laws relating length and stream number are obeyed.

A dynamic phase diagram (on the plane of vortex-vortex interaction strength vs. driving force) obtained by C. J. Olson et al. (Michigan) indicates that at least two dynamic phases of flux flow appear, depending upon the vortex-vortex interaction strength. When the vortex lattice is soft, the vortices flow in independently moving channels with smectic structure. For stiff vortex lattices, adjacent channels become locked together, producing crystalline-like order in a coupled-channel phase. The system produces maximum voltage noise at the crossover between these two phases.

Using numerical simulations, C. Reichhardt and F. Nori (Michigan) have observed phase locking, Arnold tongues, and Devil's staircases for vortex lattices driven at varying angles with respect to an underlying periodic pinning array. For most of the results presented, N_v, the number of vortices, is close to N_p, the number of pinning sites: N_v = 1.062 N_p. The transverse V(I) (voltage vs. current, or velocity vs. driving force) curves have a Devil's staircase structure, with plateaus occurring when the driving angles are along symmetry directions of the pinning array. Each of the plateaus corresponds to a different dynamical phase with a distinctive vortex structure and flow pattern.

Using the diagrammatic functional method for the effective action, S. Grundberg and J. Rammer (Umea) have developed a self-consistent mean- field theory for the dynamic melting transition of a driven vortex lattice. The results corroborate the phase diagram (on the plane of driving force vs. temperature) predicted by the phenomenological shaking theory, and the obtained melting curve is in good quantitative agreement with both the phenomenological theory and simulations.

A preprint by A. V. Nikulov (Chernogolovka) argues that the concept of vortex-lattice melting in the mixed state of type-II superconductors is "science fiction" based on incorrect notions about the Abrikosov state and incorrect definitions of phase coherence. To explain the resistive properties of superconductors with strong disorder, the author suggests a return to the Mendelssohn sponge model [K. Mendelssohn, Proc. Roy. Soc. 152A, 34 (1935)].

RBa2Cu3O7-d

As reported by K. Segawa and Y. Ando (CRIEPI), the in-plane normal-state resistivity of Zn-doped YBa2Cu3O7-d single crystals has been measured to low temperatures by suppressing superconductivity with magnetic fields up to 18 T. Substitution of Cu by Zn in the CuO2 planes was found to induce carrier localization at low temperatures in clean samples with k_Fl > 5, where since the mean free path l is larger than the electron wavelength, localization is not normally expected. The authors suggest destruction of the local antiferromagnetic correlation among Cu spins by Zn as a possible origin of this unusual charge localization.

Measurements by A. N. Lavrov et al. (Novosibirsk) of the out-of-plane resistivity rho_c of heavily underdoped RBa2Cu3O6+x (R = Tm and Lu) single crystals show that the c-axis conductivity sigma_c contains two contributions. One of these is the familiar semiconductor-like conductivity usually observed in moderately underdoped samples. The other looks metal-like and dominates the interplane transport at low temperatures and low doping, where the CuO chains are destroyed. Because of this contribution, the resistivity anisotropy rho_c/rho__[ab] saturates at low T instead of diverging. The metal-like part of sigma_c is blocked by antiferromagnetic coupling.

As reported by V. N. Narozhnyi (Troitsk and Dresden) et al., in Al-free PrBa2Cu3O7-d single crystals, the kink in the temperature dependence of the magnetic susceptibility chi_[ab](T) connected with Pr antiferromagnetic ordering disappears after field cooling (FC) in a field H||ab. However, the kink in chi_c(T) remains unchanged after FC in H||c. The authors suggest an explanation in terms of magnetic coupling between the Pr and Cu(2) sublattices, in which antiferromagnetic ordering in the Pr^[3+] sublattice is suppressed by freezing of the Cu moments in the ab plane after FC in H||ab.

YBCO bulk materials have been crystallized by P. Schaetzle et al. (Dresden) using a multi-seeded melt-growth process. Up to four biaxially oriented Sm-123 seeds were placed on top of rectangular YBCO bars (up to 100 x 40 x 15 mm^3). The resulting grains of YBCO were joined by partially coherent grain boundaries with improved current- transport capability and high levitation forces.

Entrapped spherical pores occur in YBa2Cu3O7-d crystals melt-textured without additives. However, C.-J. Kim (KAERI) et al. report that the pores entrapped within Y-123 crystals melt-textured with 5 wt% BaCeO3 are elongated and aligned parallel to the (100), (010), and (001) growth planes of the Y-123 crystals.

A microscopic description of grain boundaries in YBa2Cu3O7-d is given in two papers by S. V. Stolbov et al. (TCSUH). In the first paper, the authors carried out electronic structure calculations for several fragments of grain boundaries, and they found that the number of broken Cu-O bonds in the CuO2 plane at the interface affects the local density N_[Cu](0) of d_[Cu]-electron states at the Fermi level. In the second paper, the authors use spin-fluctuation theory, in which N_[Cu](0) controls the superconductivity, to estimate the superconducting properties of grain boundaries in YBCO and BSCCO.

Two papers by M. K. Mironova et al. (TCSUH) report transmission electron microscopy (TEM) studies shedding light on why grain boundaries in melt- textured YBCO formed by the liquid-phase-removal method (LPRM) carry high currents and do not show a strong dependence on misorientation angle.

A new approach to the preparation of biaxially textured YBCO coated tape conductors is proposed by M. Staines et al. (IRL-Lower Hutt). Using a dynamic magnetic grain-alignment technique, a biaxially aligned dispersion of orthorhombic Y-247 powder is settled on untextured silver substrates. In a subsequent heat treatment, the Y-247 is transformed to Y-123 and CuO involving a partial melt. Critical current densities at 77 K in self-field of up to 5 kA/cm^2 have been obtained in films from 10 to 30 micrometers thick, showing a clear enhancement of Jc relative to identically prepared untextured or uniaxially textured samples. Jc appears to be limited at present by the difficulty of achieving fully densified films while retaining biaxial texture. The authors note that, provided significant improvements in Jc can be obtained, this method offers an alternative to coated-tape processes based on epitaxial growth. The new method does not demand textured substrates, and it can give much higher fill factors.

Bi Cuprates

The effect of preparation of precursor powders on the formation of Bi- 2223 phase and the critical current density Jc of oxide-powder-in-tube (OPIT) tapes has been studied by A. Polasek et al. (Rio). The precursors were prepared by one-powder and two-powder methods. The authors found that tapes prepared from one-powder precursor had double the Jc of the tapes made from two-powder precursors.

A preprint by X. L. Wang et al. (Wollongong) reports observations by optical microscopy and x-ray diffraction of the growth mechanism of Bi- 2212 and Bi-2201 crystals grown at the surface of KCl flux. The authors found that the growth of Bi-2212 crystals is typically spiral-mediated, while Bi-2201 crystals grow layer-by-layer. The Bi-2212 crystals grown on a KCl surface were soft and could be bent freely, while no softening was observed for the Bi-2201 crystals. TEM studies revealed abundant dislocation networks in the softened Bi-2212 crystals.

Measurements of the low-amplitude ac susceptibility of intact and deformed Bi-2223/Ag tapes are reported by P. N. Mikheenko (Wollongong) as a function of temperature, frequency, ac amplitude, and dc magnetic field. The deformation resulted in the splitting of the chi"(T) peak into three peaks situated near 30 K, 58 K, and 90 K. The author identifies these temperatures as the Kosterlitz-Thouless temperatures of low-number stacks of superconducting layers.

Borocarbides

The Hall resistivity rho_[xy] of polycrystalline LuNi2B2C has been measured by V. N. Narozhnyi (Troitsk, Dresden, and Wroclaw) et al. and found to be negative in both the normal and mixed states, and thus not to have the sign reversal that is typical for high-Tc superconductors. The authors found a distinct nonlinearity in the dependence of rho_[xy] upon magnetic field in the normal state for T <= 40 K, and a large magnetoresistance reaching 90% for mu_0H = 16 T at T = 20 K. The scaling relation rho_[xy] proportional to rho_[xx]^[beta] (where rho_[xx] is the longitudinal resistivity) was found in the mixed state, with the value of beta depending on the degree of disorder (beta = 2.0+- 0.1 for an annealed sample and 1.7+-0.1 for an unannealed sample).

Applications

A hybrid superconductor-magnet bearing system, based on passive magnetic levitation and the flux-pinning effect of high-temperature superconductivity, has been developed by E. J. Lee (TCSUH and NASA Johnson Space Center) et al. The rationale lies in the unique capability of high-temperature superconductors to adapt to the low temperatures and vacuum environments in space or on the moon, and to enhance system stability passively without power consumption. The authors report characterization experiments, which show that the present hybrid HTS-magnet bearing system has small periodic oscillations of drag torque. The authors suggest design guidelines for future superconducting bearing systems.

Theory

The evolution of the 41 meV resonance seen in inelastic neutron- scattering experiments in optimally doped YBa2Cu3O7-d has been studied by J. Brinckmann and P. A. Lee (MIT) using slave-boson theory for the t- t'-J model. The resonance appears in this theory as a collective spin fluctuation in the d-wave superconducting state. It is undamped at optimal doping because of a threshold in the excitation energies of particle-hole pairs with relative wave vector (pi,pi). When hole filling is reduced, the resonance moves to lower energies and broadens. Below the resonance energy, the authors find a crossover to an incommensurate response, in agreement with a recent experiment on YBa2Cu3O6.6. The authors show that dynamic nesting in the d-wave superconducting state causes this effect.

The spatial variation of the order parameter near the surface of a d- wave superconductor has been calculated self-consistently by J.-X. Zhu (TCSUH) et al. using an extended Hubbard model. The authors find that a d + is order parameter can be induced near a {110} surface, leading to splitting of the zero-energy peak in the surface local density of states and the generation of a spontaneous surface supercurrent. This splitting can be diminished by increases of orthorhombicity, on-site repulsive interaction, or temperature. The results give a microscopic explanation for the surface broken-time-reversal-symmetry pairing state.

The temperature dependencies of the specific heat and spin susceptibility of a coupled d_[x^2-y^2] + id_[xy] superconductor in the presence of a weak d_[xy] component have been investigated by A. Ghosh and S. K. Adhikari (Sao Paulo) using the tight-binding model on a square lattice and on a lattice with orthorhombic distortion. As the temperature is lowered below the critical temperature Tc, first a less ordered d_[x^2-y^2] superconductor is created, which changes to a more ordered d_[x^2-y^2] + id_[xy] superconductor at T_[c1] ( The symmetry operations of the crystal groups relevant for the high- temperature superconductors HgBa2CuO4+d (Hg-1201), YBa2Cu3O7-d (Y-123), and Bi2Sr2CaCu2O8+d (Bi-2212), as well as the allowable combinations of superconducting order parameter components, have been worked out by R. A. Klemm (Argonne) et al. The authors then evaluate the Josephson critical current I_c across c-axis twist junctions in the vicinity of Tc as a function of twist angle phi for each allowable order-parameter combination. The authors find that recent measurements of I_c(phi) by Q. Li et al. in Bi-2212 are consistent with an order parameter containing an s-wave component, but inconsistent with one containing a d_[x^2-y^2] component. The authors propose an improved tricrystal experiment.

A preprint by A. S. Alexandrov and R. T. Giles (Loughborough) shows that bipolaron formation leads to a d-wave Bose-Einstein condensate in cuprates. The authors find that it is the bipolaron energy dispersion rather than a particular pairing interaction that is responsible for the d-wave symmetry. The authors also explain the unusual low-temperature dependence of the penetration depth lambda(T) in terms of the localization of bosons in the random potential. Both linear positive and negative slopes of lambda(T) can occur, depending upon the random field profile.

Both large-U and small-U orbitals have been used by J. Ashkenazi (Miami) to study the electronic structure of the high-Tc cuprates. A striped structure with three types of carriers are induced: polaron-like stripons, which carry charge; quasielectrons, which carry both charge and spin; and svivons, which carry spin and lattice distortion. The author derives anomalous physical properties of the cuprates, including the behavior of the resistivity, Hall constant, and thermoelectric power. In this model, transitions between pair states of quasielectrons and stripons drive high-temperature superconductivity.

The problem of the crossover from BCS superconductivity to Bose-Einstein condensation in three dimensions has been considered by P. Pieri and G. C. Strinati (Camerino) for a system of fermions with an attractive, suitably regularized point-contact interaction. The authors include the contributions of a new class of diagrams to obtain a formulation that describes both the weak- and strong-coupling limits, and consequently results in an improved interpolation scheme for the intermediate (crossover) region.

The effect of static fluctuations in the phase of the order parameter on the normal and superconducting properties of a 2D system with attractive four-fermion interaction has been studied by V. P. Gusynin (Kiev) et al. The results show that as the temperature increases through the 2D critical temperature, the quasiparticle peaks broaden significantly, while the gap in the quasiparticle spectrum remains. The authors make use of this effect to explain the pseudogap behavior observed in high-Tc superconductors.

The correlation-driven transition from a paramagnetic metal to a paramagnetic Mott-Hubbard insulator has been studied by M. Potthoff and W. Nolting (Berlin) using the half-filled Hubbard model for thin-film geometry with d layers. Using the dynamical mean-field theory, the authors map the film problem onto a set of d single-impurity Anderson models, which are indirectly coupled via the respective baths of conduction electrons. The authors solve these impurity models at zero temperature using the exact-diagonalization algorithm.

Using the calculated electron energy band structure of Tl2Ba2CuO6+d (Tl- 2201), A. Dragulescu (Maryland) et al. have computed the dependence of the c-axis magnetoresistance on the orientation of the magnetic field for different magnitudes of the magnetic field. The authors explain the known experimental results for the in-plane rotation of the magnetic field and predict the shape of the magnetoresistance oscillations for the out-of-plane rotations of the magnetic field. The authors show how the latter oscillations can be used to reconstruct the shape of the Fermi surface and to study the coherence of interplane electron tunneling. The authors conclude that earlier observations of angular magnetoresistance oscillations (AMRO) demonstrate that the interplane electron motion is coherent in Tl-2201.

A microscopic theory of organic superconductors based on the concept of partial electron dielectrization has been developed by A. Surana (Bhilwara) et al. The authors derive self-consistent equations for the superconducting order parameter Delta and dielectric order parameter D, and they apply the theory to explain experimental results in the 2D organic superconductor kappa-(BEDT-TTF)2Cu(NCS)2. The model accounts for the coexistence of a spin-density-wave (SDW) state and superconductivity.

Other Activities

Two preprints by T. H. Johansen (Oslo) present solutions to the flux- pinning-induced magnetostriction (stresses and strains) in long type-II superconductors placed in a parallel magnetic field. One of these presents solutions for a long circular cylinder, and the other for a long rectangular slab. All stress and strain components are expressed in terms of the flux-density profile in the sample, and the results apply for any critical-state model of Jc(B) vs B. The author emphasizes the behavior in decreasing magnetic fields, which generate tensile stresses that can lead to cracking of the sample.

Measurements of the in-plane thermal conductivity kappa(T,B) of superconducting crystals of YBa2Cu3O7-d (Y-123), YBa2Cu4O8 (Y-124), and Bi2Sr2CaCu2O8+d (Bi-2212) as a function of temperature (10 K <= T <= 150 K) and magnetic field (B <= 9 T) for different orientations of the magnetic field (B||c and B perperdicular to c) are reported by A. N. Taldenkov et al. (Leipzig). The authors found that kappa depends on B even above the critical temperature because of the contribution of superconducting fluctuations. They also found for a Bi-2212 crystal that kappa increases with field for B perperdicular to c and T < 20 K.

Overviews

A book chapter summarizing the present knowledge about the nature of defects and microstructural processes in melt-textured RBa2Cu3O7-d (R- 123, R = rare earth) superconductors has been prepared by F. Sandiumenge (Barcelona) and J. Rabier (Poitiers). The authors note that while some principles learned from Y-123 can be applied to other R-123 compounds, the discovery of Nd-123 has dramatically widened the scope of microstructural studies in the 123 system. Future challenges include (a) optimization of interfacial flux pinning in melt-textured Nd-123, (b) control of the distribution and properties of antisite defects, (c) building of 3D dislocation substructures through R cation substitutions and deformation processing, and (d) exploration of new low-temperature deformation routes (131 refs.).

A brief introduction to the high-temperature superconducting oxides is given in a preprint by D. Pavuna (EPFL-Lausanne). The author emphasizes that these materials are: (a) highly anisotropic layered oxides dominated by the properties of the CuO2 planes, (b) quasi-two- dimensional doped insulators with an anomalous normal state, (c) superconductors with Tc ~ 100 K, and (d) extreme type-II superconductors with short coherence lengths (xi ~ a few Angstroms) and large penetration depths (lambda ~ 2000 Angstroms) (13 refs.).

Ph.D. Thesis

Investigations of substitution effects and magnetic properties of various high-temperature superconductors in the R-Ba-Cu-O family are reported in the Ph.D. thesis of G. Boettger (ETH-Zurich). The author used elastic and inelastic neutron scattering, x-ray diffraction, magnetic susceptibility, and specific-heat measurements to study the pseudogap in HoBa2Cu4O8 (Ho-124) and Er2Ba4Cu7O15-d (Er-247), Ca doping in RBa2Cu3O7-d (R-123, R = Y and Er), and magnetic ordering of the rare- earth ions in R2Ba4Cu7O15-d (R-247, R = Er and Dy) (144 refs.).

Contributed by John R. Clem

Contents: Preprints begin on page 6; Coming Events begin on page 13; and FYI is on page 14.

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.

A. S. Alexandrov and R. T. Giles, "d-Wave Bose-Einstein Condensation and the London Penetration Depth in Superconducting Cuprates." Submitted to Phys. Rev. Lett. Department of Physics, Loughborough University, Loughborough LE11 3TU, UNITED KINGDOM; R. T. Gile's telephone +44 1509- 223315 or -228409; telefax +44 1509-223986; e-mail r.t.giles@lboro.ac.uk; preprint also available at cond-mat@xxx.lanl.gov (#9811270). 74.20.-z; 74.20.Mn.

M. K. Aliev, G. R. Alimov, I. Kholbaev, L. I. Leonyuk, T. M. Muminov, B. A. Olimov, R. F. Rumi, and H. I. Turkmenov, "Magnetically and Thermally Modulated Microwave Absorption in Y1Ba2Cu3O7-x Single Crystal Near Tc." Contact G. R. Alimov, Institute of Applied Physics, Tashkent State University, 700095 Tashkent, UZBEKISTAN; e-mail gleb@iaph.silk.org; preprint also available at cond-mat@xxx.lanl.gov (#9810004). Key words: temperature modulation, magnetic-field modulation, superconducting transition, microwave absorption, high-Tc superconductor.

R. P. Aloysius, A. Sobha, P. Guruswamy, K.G.K. Warrier, and U. Syamaprasad, "Optimization of Tape Width and Powder Packing Density in the Powder-in-Tube Processing of (Bi,Pb)-2223 Tapes." To be published in Physica C (in press). Contact U. Syamaprasad, Regional Research Laboratory (CSIR), Trivandrum 695 019, INDIA; telefax +91 471 491712; e-mail smail@csrrltrd.ren.nic.in. Key words: (Bi,Pb)-2223/Ag tapes, tape width, packing density, core density, critical current density. 74.72.Hs; 85.25.Kx.

Steven M. Anlage, D. E. Steinhauer, C. P. Vlahacos, B. J. Feenstra, A. S. Thanawalla, Wensheng Hu, Sudeep K. Dutta, and F. C. Wellstood, "Superconducting Material Diagnostics Using a Scanning Near-Field Microwave Microscope." To be published in IEEE Trans. Appl. Supercond.: Proc. of the 1998 Appl. Supercond. Conf. (ASC), Palm Desert, Calif., Sept. 13-18, 1998. Center for Superconductivity Research, Department of Physics, University of Maryland, College Park, MD 20742-4111; B. J. Feenstra's telephone (301) 405-6132; telefax (301) 314-9541; e-mail feenstra@squid.umd.edu; preprint also available at cond-mat@xxx.lanl.gov (#9811158).

J. Ashkenazi, "Stripes, Electron-Like and Polaron-Like Carriers, and High-Tc in the Cuprates." To be published in J. Supercond. Department of Physics, University of Miami, P.O. Box 248046, Coral Gables, FL 33124; e-mail ashkenazi@phyvax.ir.miami.edu; preprint also available at cond-mat@xxx.lanl.gov (#9811261). Key words: high-Tc superconductivity, stripes, transport properties, mechanism.

M. Ausloos, "The Intrinsic Effects of a Magnetic Field on the Microwave Properties of s- or d-Order Parameter Symmetry High Tc Superconductors." To be published in Supercond. Sci. & Technol. SUPRAS, Institute of Physics, University of Liege, B5 Sart Tilman, B-4000 Liege, BELGIUM; e- mail ausloos@gw.unipc.ulg.ac.be; Web site http://www.phe.ulg.ac.be/. 74.25.Nf; 74.60.Ec; 72.10.-d.

M. Ausloos, H. Bougrine, M. Houssa, and M. Pekala, "Comment on 'Observation of Vortex-Lattice Melting in YBaCuO by Seebeck-Effect Measurements.'" To be published in Phys. Rev. B. SUPRAS, Institute of Physics, University of Liege, B5 Sart Tilman, B-4000 Liege, BELGIUM; e- mail ausloos@gw.unipc.ulg.ac.be. 74.60.Ec; 74.72.Bk; 74.25.Fy.

N. Bontemps, H. Enriquez, and Y. DeWilde, "Vortex Lattice and Dissipation Related Properties at High Frequency in Layered High-Tc Superconductors." Submitted to Phys. and Mater. Sci. of Vortex States, Flux Pinning, and Dynamics: Proc. of the NATO Adv. Study Inst., Kusadasi, Turkey, July 26-Aug. 8, 1998; edited by R. Kossowsky, S. M. Bose, V. Pan, and H. Z. Durusoy (Kluwer, 1999). Laboratoire de Physique de la Matiere Condensee, Ecole Normale Superieure, 24 rue Lhomond, F- 75231 Paris Cedex 05, FRANCE.

Grit Boettger, "Investigation of High-Temperature Superconductors of the R-Ba-Cu-O Family: Substitution Effects and Magnetic Properties." Submitted as a Ph.D. thesis (Swiss Federal Institute of Technology Zurich). Laboratorium fuer Kristallographie, ETH Zurich, Sonneggstr.5, CH-8092 Zurich, SWITZERLAND; telephone +41 1 632 30 56; telefax +41 1 632 11 33; e-mail grit@kristall.erdw.ethz.ch.

Jan Brinckmann and Patrick A. Lee, "Slave Boson Approach to the Neutron Scattering in YBa2Cu3O6+y Superconductors." TKM/Physik, Universitaet Karlsruhe, Postfach 6980, D-76128 Karlsruhe, GERMANY; e-mail janbri@tkm.physik.uni-karlsruhe.de; preprint also available at cond- mat@xxx.lanl.gov (#9811038). 71.10.Fd; 74.25.Ha; 74.72.Bk; 75.20.Hr.

A. M. Campbell, "Fields and Losses in High-Tc Conductors." Presented at the 1998 Appl. Supercond. Conf. (ASC), Palm Desert, Calif., Sept. 13-18, 1998. Interdisciplinary Research Centre in Superconductivity, University of Cambridge, Madingley Road, Cambridge CB3 0HE, UNITED KINGDOM; telephone +44 1223 337-078 or -076; telefax +44 1223 337-074; e-mail amc1@cam.ac.uk.

F. Cordero and R. Cantelli, "Interstitial O and O Vacancies in La2CuO4+d During High Temperature Treatments." Submitted to Physica C. Istituto di Acustica "O.M. Corbino," CNR, Area di Ricerca di Roma-Tor Vergata, Via del Fosso del Cavaliere 100, I-00133 Rome, ITALY; telephone +39 06 4993 4114; telefax +39 06 2066 0061; e-mail cordero@idac.rm.cnr.it. Key words: La2CuO4+d, interstitial O, O vacancies. 64.30.+t; 74.72.Dn; 61.72.Ji.

G. D'Anna, V. Berseth, L. Forro, A. Erb, and E. Walker, "Scaling of the Hall Resistivity in the Solid and Liquid Vortex Phases in Twinned Single Crystal YBa2Cu3O7-d." Institut de Genie Atomique, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne, SWITZERLAND; e-mail danna@igahpse.epfl.ch; preprint also available at cond-mat@xxx.lanl.gov (#9811106). 74.25.Fy; 74.60.Ge; 74.72.Bk.

O. D. Danyliv, "Phase Transitions in the Two-Sublattice Pseudospin- Electron Model of High Temperature Superconducting Systems." To be published in Physica C (in press). Institute for Condensed Matter Physics, Ukrainian Academy of Sciences, 1 Svientsitsky St., UA 290011 Lviv, UKRAINE; telefax +380 322 761978; e-mail danyliv@icmp.lviv.ua. Key words: Hubbard model, local anharmonicity, phase transitions. 05.70.-a; 74.72.Bk.

Adrian Dragulescu, Victor M. Yakovenko, and David J. Singh, "Theory of Angular Magnetoresistance Oscillations in Tl2Ba2CuO6." Center for Superconductivity Research and Department of Physics, University of Maryland, College Park, MD 20742-4111; Victor M. Yakovenko's e-mail yakovenk@physics.umd.edu; preprint also available at cond- mat@xxx.lanl.gov (#9811101). 74.72.Fq; 72.15.Gd.

L. M. Fisher, A. V. Kalinov, S. E. Savel'ev, I. F. Voloshin, and V. A. Yampol'skii, "Critical Current Anisotropy in YBCO Superconducting Samples." To be published in Physica C (in press). All-Russian Electrical Engineering Institute, 12 Krasnokazarmennaya Str., 111250 Moscow, RUSSIA; telephone +7 095 361 9226; telefax +7 095 361 9226. Key words: high-Tc superconductors, flux pinning and creep.

S. C. Gadkari and S. K. Gupta, "An Instrument for Automatic Measurements of Critical Current of Superconductors in Pulse Mode." Submitted to Rev. Sci. Instrum. Technical Physics and Prototype Engineering Division, Bhabha Atomic Research Center, Mumbai 400 085, INDIA; telefax +91 22 550 5151; e-mail tfds@apsara.barc.ernet.in.

Angsula Ghosh and Sadhan K. Adhikari, "Phase Transition from a d_[x^2- y^2] to d_[x^2-y^2] + id_[xy] Superconductor." To be published in Physica C (in press). Contact Sadhan K. Adhikari, Instituto de Fisica Teorica, Universidade Estadual Paulista, Rua Pamplona 145, 01405-900 Sao Paulo, S.P., BRAZIL; telefax +55 11 288 8224; e-mail adhikari@ift.unesp.br. Key words: d_[x^2-y^2] + id_[xy]-wave superconductor, specific heat, susceptibility. 74.20.Fg; 74.62.-c; 74.25.Bt.

Staffan Grundberg and Jorgen Rammer, "Self-Consistent Theory of Dynamic Melting of a Vortex Lattice." To be published in Europhys. Lett. Department of Theoretical Physics, Umea University, S-901 87 Umea, SWEDEN; telephone +46 90 786 59 41; telefax +46 90 786 95 56; e-mail grundberg@tp.umu.se; preprint also available at cond-mat@xxx.lanl.gov (#9811154). 74.60.Ge; 05.40.+j; 03.65.Db.

V. P. Gusynin, V. M. Loktev, and S. G. Sharapov, "Phase Fluctuations and Single Fermion Spectral Density in 2D Systems with Attraction." Bogolyubov Institute for Theoretical Physics, 252143 Kiev, UKRAINE; e- mail vgusynin@bitp.kiev.ua; preprint also available at cond- mat@xxx.lanl.gov (#9811207). 74.25.-q; 74.40.+k; 74.72.-h.

Tadahiro Hosomi, Hisayuki Suematsu, Helmer Fjellvag, Yoshio Matsui, Yoshitsugu Tomokiyo, Maarit Karppinen, and Hisao Yamauchi, "Investigation of an Unstable Tc ~~ 126 K Phase and Its Derivative Phase in the Ba-Ca-Cu-O System." Submitted to Advances in Supercond. XI: Proc. of the 11th Int. Symp. on Superconductivity (ISS'98), Fukuoka, Japan, Nov. 16-19, 1998; edited by N. Koshizuka and S. Tajima (Springer- Verlag, Tokyo). Contact Hisao Yamauchi, Materials & Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 227, JAPAN; telephone +81 45 924-5315; telefax +81 45 924-5365 or -5360; e-mail yamauchi@materia.titech.ac.jp. Key words: unstable Ba-Ca-Cu-O phases, synchrotron XRD, structural models, irreversibility field.

Y. K. Huang, B. ten Haken, and H.H.J. ten Kate, "Critical Current of High Tc Superconducting Bi2223/Ag Tapes." To be published in Physica C (in press). Faculty of Applied Physics, Low Temperature Division, University of Twente, P.O. Box 217, 7500 AE Enschede, THE NETHERLANDS; telephone +31 53 489 3140; telefax +31 53 489 1099; e-mail y.huang@tn.utwente.nl. Key words: critical current, weak links, flux pinning.

Tom H. Johansen, "Flux-Pinning-Induced Stress and Strain in Superconductors -- Long Circular Cylinder." Submitted to Phys. Rev. B. Department of Physics, University of Oslo, P.O. Box 1048, Blindern, N- 0316 Oslo, NORWAY; telephone +47 22 85 6428; telefax +47 22 85 6422.

Tom H. Johansen, "Flux-Pinning-Induced Stress and Strain in Superconductors -- Long Rectangular Slab." Submitted to Phys. Rev. B. Department of Physics, University of Oslo, P.O. Box 1048, Blindern, N- 0316 Oslo, NORWAY; telephone +47 22 85 6428; telefax +47 22 85 6422.

Chan-Joong Kim, Gye-Won Hong, and Suk-Joong L. Kang, "Entrapment of Elongated and Crystallographically Aligned Pores in YBa2Cu3O7-y Melt- Textured with BaCeO3 Addition." To be published in J. Mater. Res. Superconductivity Research Laboratory, Korea Atomic Energy Research Institute, P.O. Box 105, Yusong, Taejon 305-600, SOUTH KOREA; telephone +82 42 868 8908; telefax +82 42 862 5496; e-mail cjkim2@nanum.kaeri.re.kr.

R. A. Klemm, C. T. Rieck, and K. Scharnberg, "Order Parameter Symmetries in High Temperature Superconductors." Submitted to Phys. Rev. B. Materials Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439; e-mail klemm@anl.gov; preprint also available at cond-mat@xxx.lanl.gov (#9811303).

A. N. Lavrov, M. Yu. Kameneva, and L. P. Kozeeva, "Normal-State Resistivity Anisotropy in Underdoped RBa2Cu3O6+x Crystals." To be published in Phys. Rev. Lett. Electrical Physics Department, Komae Research Laboratory, Central Research Institute of Electric Power Industry, 2-11-1 Iwado-kita, Komaeshi, Tokyo 201-8511, JAPAN; telephone +81 3 3480 2111; telefax +81 3 3480 3401; e-mail lavrov@criepi.denken.or.jp; preprint also available at cond- mat@xxx.lanl.gov (#9811104). 74.25.Fy; 74.62.Dh; 74.72.Bk.

M. Leadbeater, C. J. Lambert, R. Raimondi, and A. F. Volkov, "Sub-Gap Conductance in Ferromagnetic-Superconducting Mesoscopic Structures." Dipartimento di Fisica, Universita di Roma Tre, Via della Vasca Navale 84, I-00146 Rome, ITALY; R. Raimondi's e-mail bob@roberto.fis.uniroma3.it; preprint also available at cond- mat@xxx.lanl.gov (#9811117). 74.50.+r; 72.15.Nj.

E. J. Lee, K. B. Ma, T. L. Wilson, and W. K. Chu, "Characterization of Superconducting Bearings for Lunar Telescopes." Preprint #98:119; submitted to IEEE Trans. Appl. Supercond.: Proc. of the 1998 Appl. Supercond. Conf. (ASC), Palm Desert, Calif., Sept. 13-18, 1998. 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.

A. P. Mehta, C. Reichhardt, C. J. Olson, and Franco Nori, "Topological Invariants in Microscopic Transport on Rough Landscapes: Morphology and Horton Analysis of River-Like Networks of Vortices." Submitted to Phys. Rev. Lett. Contact Franco Nori, Department of Physics, University of Michigan, Ann Arbor, MI 48109-1120; telephone (734) 764-3271; telefax (734) 763-9694; e-mail nori@umich.edu. 64.60.Ht; 74.60.Ge; 92.40.Fb.

P. N. Mikheenko, "Discrete Temperatures in High Temperature Superconductors." To be published in Physica C. Centre for Superconducting and Electronic Materials, University of Wollongong, Northfields Avenue, Wollongong, NSW 2522, AUSTRALIA; telephone +61 42 21 5726; telefax +61 42 21 5731; e-mail mikhe@uow.edu.au. Key words: ac susceptibility, Cu-O planes, critical current density, fluctuation effects, interlayer pairing.

M. K. Mironova, G. P. Du, and K. Salama, "Measurements of Misorientation Angles Over a Large Distance in Strongly Coupled Grain Boundaries." Preprint #98:126; submitted to IEEE Trans. Appl. Supercond.: Proc. of the 1998 Appl. Supercond. Conf. (ASC), Palm Desert, Calif., Sept. 13-18, 1998. 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.

M. K. Mironova, S. V. Stolbov, G. P. Du, and K. Salama, "Contribution of Grain Boundary Planes to Superconducting Coupling in YBCO." Preprint #98:125; submitted to the Proc. of the 1998 Appl. Supercond. Conf. (ASC), Palm Desert, Calif., Sept. 13-18, 1998; to be published in IEEE Trans. Appl. Supercond. 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.

K.-H. Mueller, "ac Losses in Stacks and Arrays of YBCO/Hastelloy and Monofilamentary Bi-2223/Ag Tapes." To be published in Physica C. Telecommunications and Industrial Physics, CSIRO, Bradfield Road, West Lindfield, Lindfield NSW 2070, AUSTRALIA; telephone +61 2 9413 7052; telefax +61 2 9413 7202; e-mail karl@tip.csiro.au. Key words: ac losses, coated conductors, YBCO/Hastelloy, Bi-2223/Ag tapes. 85.25.Kx; 84.70.+p; 74.76.Bz; 74.25.Fy.

T. Muroga, J. Sato, H. Kitaguchi, H. Kumakura, K. Togano, and M. Okada, "Enhancement of Critical Current Density for Bi-2212/Ag Tape Conductors Through Microstructure Control." To be published in Physica C (in press). Advanced Research Center, Hitachi Cable, 3550 Kidamari, Tsuchiura, Ibaraki 300-0026, JAPAN; telephone +81 298 26 7658; telefax +81 298 26 6411; e-mail muroga@arc.hitachi-cable.jp. Key words: Bi- 2212/Ag tape, dip-coating, oxide/Ag interface, grain alignment, Jc.

Takayuki Nakane, Kyoichi Fujinami, Maarit Karppinen, and Hisao Yamauchi, "Hole Distribution and Magnetic-Field Irreversibility in Cu(Ba0.8Sr0.2)2(Yb1-xCax)Cu2O6+z." Submitted to Advances in Supercond. XI: Proc. of the 11th Int. Symp. on Superconductivity (ISS'98), Fukuoka, Japan, Nov. 16-19, 1998; edited by N. Koshizuka and S. Tajima (Springer- Verlag, Tokyo). Contact Hisao Yamauchi, Materials & Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 227, JAPAN; telephone +81 45 924-5315; telefax +81 45 924-5365 or -5360; e-mail yamauchi@materia.titech.ac.jp. Key words: hole distribution, irreversibility field, BVS, XANES.

V. N. Narozhnyi and S.-L. Drechsler, "Comment on 'Superconducting PrBa2Cu3Ox.'" To be published in Phys. Rev. Lett. Institute for High Pressure Physics, Russian Academy of Sciences, Troitsk, Moscow Region 142092, RUSSIA; telephone +7 095 334 0808; telefax +7 095 334 0012; e- mail narozh@ns.hppi.troitsk.ru; preprint also available at cond- mat@xxx.lanl.gov (#9811268).

V. N. Narozhnyi, D. Eckert, K. A. Nenkov, G. Fuchs, T. G. Uvarova, and K.-H. Mueller, "Anomalous Magnetic Ordering in PrBa2Cu3O7-y Single Crystals: Evidence for Magnetic Coupling Between the Cu and Pr Sublattices." To be published in Physica C. Institute for High Pressure Physics, Russian Academy of Sciences, Troitsk, Moscow Region 142092, RUSSIA; telephone +7 095 334 0808; telefax +7 095 334 0012; e- mail narozh@ns.hppi.troitsk.ru; preprint also available at cond- mat@xxx.lanl.gov (#9811271). Key words: antiferromagnetic order, magnetic susceptibility, magnetization, single crystal, PrBa2Cu3O7-y. 74.72.Bk; 75.50.Ee; 75.25.+z; 75.30.Gw.

V. N. Narozhnyi, J. Freudenberger, V. N. Kochetkov, K. A. Nenkov, G. Fuchs, and K.-H. Mueller, "Hall-Effect in LuNi2B2C in Normal and Superconducting Mixed States." To be published in Solid State Commun. Institute for High Pressure Physics, Russian Academy of Sciences, Troitsk, Moscow Region 142092, RUSSIA; telephone +7 095 334 0808; telefax +7 095 334 0012; e-mail narozh@ns.hppi.troitsk.ru; preprint also available at cond-mat@xxx.lanl.gov (#9811273). Key words: superconductors, electronic transport, galvanomagnetic effects.

A. V. Nikulov, "Vortex Lattice Melting Theories as Example of Science Fiction." Presented at the NATO Advanced Research Workshop on Symmetry and Pairing in Superconductors, Yalta, Crimea, Ukraine, April 28-May 2, 1998. Institute of Microelectronics Technology and High Purity Materials, Russian Academy of Sciences, 142432 Chernogolovka, Moscow District, RUSSIA; telephone +7 095 521 5183; telefax +7 095 962 8047; e- mail nikulov@ipmt-hpm.ac.ru; preprint also available at cond- mat@xxx.lanl.gov (#9811051).

C. J. Olson, C. Reichhardt, and Franco Nori, "Nonequilibrium Dynamic Phase Diagram for Vortex Lattices." Submitted to Phys. Rev. Lett. Department of Physics, University of Michigan, Ann Arbor, MI 48109-1120; Franco Nori's telephone (734) 764-3271; telefax (734) 763-9694; e-mail nori@umich.edu. 74.60.Ge.

Xavier Oudet, "Conductivity and Statistics: Is an Alternative View Possible?" English version of "Conductivite et Statistique: Une Approche Differente Est-Elle Possible?" to be published in Annales de la Fondation Louis de Broglie. Laboratoire de Magnetisme et d'Optique, Batiment Fermat, Universite de Versailles, C.N.R.S., 45 Avenue des Etats-Unis, F-78035 Versailles Cedex, FRANCE; telephone +33 1 3925 4654; e-mail xavier.oudet@physique.uvsq.fr.

S. Patnaik, R. C. Budhani, Y.-L. Wang, and M. Suenaga, "Radio Frequency Vortex Dynamics in Oriented Platelets of (Bi-Pb)2Sr2Ca2Cu3O10 Superconductor." To be published in Physica C (in press). Contact R. C. Budhani, Department of Physics, Indian Institute of Technology, Kanpur 208 016, INDIA; telephone +91 512 59 7185; e-mail rcb@iitk.ernet.in. Key words: radio frequency, vortex dynamics, Lorentz force.

Davor Pavuna, "Introduction to High Temperature Superconducting Oxides." To be published in The Gap Symmetry and Fluctuations in High-Tc Supercond., edited by Bok et al. (Plenum Press, New York, 1998). Department of Physics, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne, SWITZERLAND.

M. Pekala and M. Ausloos, "Vortex Lattice Melting Probed by Nernst Effect." To be published in Phys. and Mater. Sci. of Vortex States, Flux Pinning, and Dynamics: Proc. of the NATO Adv. Study Inst., Kusadasi, Turkey, July 26-Aug. 8, 1998; edited by R. Kossowsky, S. M. Bose, V. Pan, and H. Z. Durusoy (Kluwer, 1999). Department of Chemistry, University of Warsaw, Al. Zwirki i Wigury 101, PL 02-089 Warsaw, POLAND; M. Ausloos' e-mail at University of Liege, Belgium, ausloos@gw.unipc.ulg.ac.be.

A. M. Petrean, L. M. Paulius, W.-K. Kwok, J. A. Fendrich, and G. W. Crabtree, "Experimental Evidence for the Vortex Glass Phase in Untwinned, Proton Irradiated YBa2Cu3O7-d." Contact Janice Coble, Materials Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439; telephone (630) 252-5497; telefax (630) 252- 9595; e-mail coble@anl.gov. 74.25.Dw; 74.25.Fy; 74.62.Dh; 74.60.Ge.

P. Pieri and G. C. Strinati, "On the Correct Strong-Coupling Limit in the Evolution from BCS Superconductivity to Bose-Einstein Condensation." Dipartimento di Matematica e Fisica, Sezione INFM, Universita di Camerino, Via Madonna delle Carceri, I-62032 Camerino, ITALY; telephone +39 073 7402534; telefax +39 073 7632525; e-mail pieri@str.unicam.it; preprint also available at cond-mat@xxx.lanl.gov (#9811166). 74.25.-q; 74.20.-z; 05.30.Jp.

A. Polasek, S. K. Xia, M. B. Lisboa, M. A. Sens, E. T. Serra, F. Rizzo, and H. Borges, "The Influence of Precursor Preparation on the Superconducting Properties of Bi(2223) Tapes." Submitted to the Proc. of the 1998 Appl. Supercond. Conf. (ASC), Palm Desert, Calif., Sept. 13- 18, 1998. Centro de Pesquisas de Energia Eletrica (CEPEL), P.O. Box 68007, CEP 21944-970, Rio de Janeiro, BRAZIL; e-mail polasek@fund.cepel.br.

M. Potthoff and W. Nolting, "Dynamical Mean-Field Study of the Mott Transition in Thin Films." To be published in Eur. Phys. J. B (in press). Institut fuer Physik, Humboldt-Universitaet zu Berlin, D-10115 Berlin, GERMANY; e-mail potthoff@orion.physik.hu-berlin.de; preprint also available at cond-mat@xxx.lanl.gov (#9811137).

Pratap Raychaudhuri and V. V. Srinivasu, "Oscillations in Surface Resistance with Applied Magnetic Field Variation in BSCCO Aged Superconducting Samples." To be published in Solid State Commun. Contact V. V. Srinivasu, Texas Center for Superconductivity, University of Houston, Houston, TX 77204-5932; telephone (713) 743-8200; telefax (713) 743-8201; e-mail vallabha@bayou.uh.edu. Key words: high-Tc superconductors, surface resistance, Josephson junctions, magneto microwave absorption.

C. Reichhardt and Franco Nori, "Phase Locking, Devil's Staircases, and Arnold Tongues in Driven Vortex Lattices with Periodic Pinning." To be published in Phys. Rev. Lett. Department of Physics, University of Michigan, Ann Arbor, MI 48109-1120; Franco Nori's telephone (734) 764- 3271; telefax (734) 763-9694; e-mail nori@umich.edu. 74.60.Ge; 64.70.Rh; 74.60.Jg.

Marlyse Roulin, Bernard Revaz, Alain Junod, Andreas Erb, and Eric Walker, "High Resolution Specific Heat Experiments on the Vortex Melting Line in MBa2Cu3Ox (M=Y, Dy and Eu) Crystals: Observation of First- and Second-Order Transitions up to 16 T." To be published in Phys. and Mater. Sci. of Vortex States, Flux Pinning, and Dynamics: Proc. of the NATO Adv. Study Inst., Kusadasi, Turkey, July 26-Aug. 8, 1998; edited by R. Kossowsky, S. M. Bose, V. Pan, and H. Z. Durusoy (Kluwer, 1999). Departement de Physique de la Matiere Condensee, Universite de Geneve, 24 quai Ernest-Ansermet, CH-1211 Geneve 4, SWITZERLAND; e-mail marlyse.roulin@physics.unige.ch.

F. Sandiumenge and J. Rabier, "Defects and Microstructural Engineering in Melt-Textured RE123 Superconductors." To be published in Studies of High Temp. Supercond., Vol. 27-28, edited by A. Narlikar (Nova Science Publishers, New York, 1998). Institut de Ciencia de Materials de Barcelona, (CSIC), Campus de la Universitat Autonoma de Barcelona, E- 08193 Bellaterra, Catalunya, SPAIN; telephone +34 3 580 1853; telefax +34 3 580 5729.

S. Schaetzle, G. Krabbes, G. Stoever, G. Fuchs, and D. Schlaefer, "Multi-Seeded Melt Crystallization of YBCO Bulk Material for Cryogenic Applications." To be published in Supercond. Sci. & Technol. Institute of Solid State and Materials Research Dresden, P.O. Box 270016, D-01171 Dresden, GERMANY; telephone +49 351 4659 408; telefax +49 351 4659 480.

V. Sedykh, B. Sh. Bagautdinov, E. V. Suvorov, I. S. Smirnova, A. V. Dubovitskii, and V. Sh. Shekhtman, "The Effect of Pb on the Behavior of Structure Modulation in Bi2-xPbxSr3Fe2Oy Isostructural with Bi2Sr2CaCu2O8." To be published in Physica C (in press). Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, 142432 Moscow Region, RUSSIA; telephone +7 095 584 9725; telefax +7 095 576 41 11; e-mail sedykh@issp.ac.ru. Key words: Bi2-xPbxSr3Fe2Oy single crystals, modulated structures, x-ray diffraction, Mossbauer spectroscopy, transmission electron microscopy. 61.10.Lx; 61.16.Bg; 61.72.Ss; 74.62.Bf; 76.80.+y.

Kouji Segawa and Yoichi Ando, "Charge Localization from Local Destruction of Antiferromagnetic Correlation in Zn-Doped YBa2Cu3O7-d." To be published in Phys. Rev. B. Central Research Institute of Electric Power Industry, Komae, Tokyo 201-8511, JAPAN; e-mail segawa@criepi.denken.or.jp; preprint also available at cond- mat@xxx.lanl.gov (#9811278). 74.25.Fy; 74.62.Dh; 74.20.Mn; 74.72.Bk.

R. Seviour, C. J. Lambert, and A. F. Volkov, "Anomalous Transport in Normal-Superconducting and Ferromagnetic-Superconducting Nanostructures." Submitted to Phys. Rev. B. School of Physics and Chemistry, Lancaster University, Lancaster LA1 4YB, UNITED KINGDOM; e- mail seviour@unix.lancs.ac.uk; preprint also available at cond- mat@xxx.lanl.gov (#9811216). 74.25.Fy; 73.23.-b; 72.10.-d; 72.10.Bg; 73.40.Gk; 74.50.+r.

Michael Staines, Jean-Yves Genoud, Anne Mawdsley, and Veljko Manojlovic, "Thick Film Biaxially Textured YBCO Coated Tape Conductors Prepared Using Magnetic Grain Alignment." Submitted to IEEE Trans. Appl. Supercond.: Proc. of the 1998 Appl. Supercond. Conf. (ASC), Palm Desert, Calif., Sept. 13-18, 1998. Industrial Research Ltd., Gracefield Research Centre, Gracefield Road, P.O. Box 31-310, Lower Hutt, NEW ZEALAND; telephone +64 4 569 0000; telefax +64 4 566 6004.

S. V. Stolbov, M. K. Mironova, and K. Salama, "Microscopic Description of Grain Boundaries in Superconducting Copper Oxides: I. Electron Structure in the Vicinity of Grain Boundaries." Preprint #98:127; submitted to Phys. Rev. B. 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.

S. V. Stolbov, M. K. Mironova, and K. Salama, "Microscopic Description of Grain Boundaries in Superconducting Copper Oxides: II. Method to Determine Superconducting Properties." Preprint #98:128; submitted to Phys. Rev. B. 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.

Anil Surana, R. K. Paliwal, and S. L. Kakani, "Microscopic Theory of Organic Superconductors." Submitted to J. Supercond. Department of Physics, S.M.M. Govt. Girls P.G. College, Bhilwara 311 001 (Raj.), INDIA. Key words: organic superconductivity, dielectrization, Green's functions, phase transition, density of states, coexistence, spin density wave, charge density wave. 74.10.+v; 74.60.-w; 74.70.Kn; 75.10.-b; 75.40.

A. N. Taldenkov, P. Esquinazi, and K. Leicht, "Thermal Transport in High-Tc Crystals: Some Aspects on Its Temperature and Magnetic Field Dependence." To be published in J. Low Temp. Phys. Department of Superconductivity and Magnetism, University of Leipzig, Linnestrasse 5, D-04103 Leipzig, GERMANY; P. Esquinazi's telefax +49 341 9732769; e-mail esquin@physik.uni-leipzig.de. 72.15.Eb; 74.25.Fy; 74.72.Bk; 74.72.Hs.

Ashfaq S. Thanawalla, B. J. Feenstra, Wensheng Hu, D. E. Steinhauer, S. K. Dutta, Steven M. Anlage, F. C. Wellstood, and Robert B. Hammond, "Frequency Following Imaging of Electric Fields from Resonant Superconducting Devices using a Scanning Near-Field Microwave Microscope." To be published in IEEE Trans. Appl. Supercond.: Proc. of the 1998 Appl. Supercond. Conf. (ASC), Palm Desert, Calif., Sept. 13-18, 1998. Department of Physics, Center for Superconductivity Research, University of Maryland, College Park, MD 20742-4111; B. J. Feenstra's telephone (301) 405-6132; telefax (301) 314-9541; e-mail feenstra@squid.umd.edu; preprint also available at cond-mat@xxx.lanl.gov (#9811141).

A. F. Volkov, V. V. Pavlovskii, and R. Seviour, "Proximity-Induced Transport in Hybrid Mesoscopic Normal-Superconducting Metal Structures." School of Physics and Chemistry, Lancaster University, Lancaster LA1 4YB, UNITED KINGDOM; R. Seviour's e-mail seviour@unix.lancs.ac.uk; preprint also available at cond-mat@xxx.lanl.gov (#9811151).

X. L. Wang, H. K. Liu, X. Z. Liao, and S. X. Dou, "Softening of Bi2212 Crystals and Growth Mechanism of Bi2212 and Bi2201 Grown at the KCl Flux Surface." To be published in Supercond. Sci. and Technol. Institute for Superconducting and Electronic Materials, University of Wollongong, NSW 2522, AUSTRALIA; telefax +61 2 4221 5731; e-mail xlw01@uow.edu.au.

Z. H. Wang and X. W. Cao, "Effective Activation Energy U_e(T,H) in an Epitaxial GdBa2Cu3O7-d Thin Film." To be published in Solid State Commun. Shanghai Institute of Metallurgy, Chinese Academy of Sciences, Shanghai 200050, PEOPLE'S REPUBLIC OF CHINA; telephone +86 21 6251 1070, ext. 8924; telefax +86 21 6251 3510; e-mail zhwang@itsvr.sim.ac.cn. 74.60.Ge; 74.76.Bz; 74.25.Fy.

Hongjie Yan, Zhiqiang Mao, Gaojie Xu, Lei Shi, Mingliang Tian, and Yuheng Zhang, "Distortion of the Microstructure in Bi1.8Pb0.2Sr2-xCuOy System." To be published in Physica C (in press). Structure Research Laboratory, University of Science and Technology of China, Hefei, Anhui 230026, PEOPLE'S REPUBLIC OF CHINA; e-mail yanhj@mail.ustc.edu.cn. Key words: distortion, Raman scattering, electron diffraction. 74.72.Dn; 74.25.Fy.

J. X. Zhu, B. Friedman, and C. S. Ting, "A Lattice Model for the Broken- Time-Reversal-Symmetry Pairing State Near a Surface of d-Wave Superconductors." Preprint #98:108; to be published in Phys. Rev. B. Texas Center for Superconductivity, University of Houston, Houston, TX 77204-5932; telephone (713) 743-8200; telefax (713) 743-8201; e-mail preprints@www.tcs.uh.edu. 74.20.-z; 74.25.Jb; 74.50.+r.

J. X. Zhu, B. Friedman, and C. S. Ting, "Spin-Polarized Quasiparticle Transport in Ferromagnet-d-Wave Superconductor Junctions." Preprint #98:109; submitted to Phys. Rev. B. Texas Center for Superconductivity, University of Houston, Houston, TX 77204-5932; telephone (713) 743-8200; telefax (713) 743-8201; e-mail preprints@www.tcs.uh.edu. 74.20.Mn; 74.80.Fp; 74.50.+r.

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

*May 18 - 21, 1999: International Magnetics Conference (INTERMAG 99), Hotel Hyundai, Kyongju, Korea. Purpose is to provide a forum for presentation of new developments in applied magnetics, magnetic phenomena and materials, and information storage techniques. Will include sessions on superconductivity, magnetic levitation and propulsion, and microwave and millimeter-wave applications. For information, contact INTERMAG 99, The Korean Magnetics Society, Rm. 905, The Korea Science and Technology Center, Yeoksam-dong 635-4, Kangnam-ku, Seoul 135-703, Korea; telephone +82 2 967 0518; e-mail intermag@kistmail.kist.re.kr; Web site http://intermag99.kist.re.kr/.

*July 7 - 10, 1999: Ninth International Workshop on Critical Currents (IWCC9-99), University of Wisconsin, Madison, Wisconsin. IWCC9-99 will be the ninth in a series of workshops devoted to study and discussion of the critical current density in superconductors. This three and one- half day workshop will be organized around keynote talks on flux pinning, grain-boundary properties, and the current-limiting mechanisms of single- and polycrystalline superconductors. Extensive discussion time will be given to these key topics. Abstract deadline, January 31, 1999. For further information, contact M. M. Adams, Conference Coordinator, 1500 Engineering Drive, Room 917 ERB, Madison, WI 53706; telephone (608) 263-5029; telefax (608) 263-1087; e-mail iwcc@engr.wisc.edu.

*July 12 - 16, 1999: Cryogenic Engineering Conference & International Cryogenic Materials Conference (CEC/ICMC), Hotel Inter-Continental Montreal, Montreal, Quebec, Canada. The CEC focuses on the science and engineering required for cryogenic applications such as liquefied gases for fuels; space applications of cryogenic liquids; cooling and performance of superconducting magnet systems in medical, transportation, power, and basic research applications; as well as the systems, machinery, control technology, and thermodynamics required to produce low temperatures. The ICMC focuses on the development, characterization, fabrication, and optimization of the materials used in cryogenic applications, typically broken into two broad categories: structural materials and superconducting materials. ICMC contributions cover both high- and low-temperature superconducting materials from basic materials research through behavior of composite cables and wires in applications. Cryogenic structural materials cover a broad range, including nonmetallic composites, polymeric resins and insulation materials, ferrous alloys, nickel-base alloys, aluminum alloys, and specialized materials for advanced cryocooler applications. For information, contact Centennial Conferences, Suite A-112, 4800 Baseline Road, Boulder, CO 80303; telephone (303) 499-2299; telefax (303) 499- 2599; e-mail centennial@orci.com; Web site http://www.cec-icmc.org.

*July 17 - 25, 1999: 5th International Summer School and Scientific Workshop, Eger, Hungary. Organized by the SuperTech Consortium, Hungary. The objective of the Workshop is to provide an overview on the basic and up-to-date information on the theories and newest results both in fundamental research and applications of high temperature superconductors. The main framework of the School is a series of tutorial lectures, each of two-hour duration, presented by well-known scientists and experts. The lectures will be published in textbook form, and in addition, proceedings (containing the lectures and the papers of the conference, videos from the lectures, and the social programs) will be available on a CD-ROM. Round-table sessions to be organized after lectures for free discussion. Last two days of the School will be devoted to a scientific conference for participants willing to present results of their work. Abstract deadline, March 1, 1999. For more information, contact Istan Vajda, Department of Electrical Machines and Drives, Technical University of Budapest, Egry Jozsef u. 18., H-1111 Budapest, Egry Jozsef u. 18., Hungary; telephone +36 1 463 2961; telefax +36 1 463 3600; e-mail vajda@ntb.bme.hu.

August 17 - 20, 1999: 1999 Taiwan International Conference on Superconductivity (TICS'99) & 6th Workshop on Low Temperature Physics (WLTP6), Kenting, Taiwan, ROC. Continuation of the five previous TICS conferences. Topics are: superconducting materials (new, bulk, single crystal, and thin film); material characterization and physical properties; theories and applications of superconductivity; strongly correlated electron systems; and other low temperature physics-related topics. All papers will be refereed and published in the Chinese Journal of Physics (Taipei) as a special issue. Conference language is English. Abstract deadline, May 1, 1999; preregistration deadline, April 1, 1999. For information, contact Department of Physics, National Sun Yat-Sen University, Kaohsiung, Taiwan 804, Republic of China; telephone +886 7 5253701; telefax +886 7 5253709; e-mail ics99@mail.phys.nsysu.edu.tw; Web site http://www2.nsysu.edu.tw/Physics/tics99.

*Sept. 14 - 17, 1999: Fourth European Conference on Applied Superconductivity (EUCAS'99), Melia Gran Sitges, Hotel in Sitges, Barcelona, Catalonia, Spain. Aim is to provide a forum for presentation and discussion of the developments in the field of the applications of superconductivity, in both large and small scale, including the most recent advances in the subject. All aspects of applied superconductivity will be covered, from both a scientific point of view (which include contributions from the fields of physics, electronics, material properties, chemistry, and engineering), and also an industrial perspective. Conference will encourage new cooperation on European and wider international levels. The program will be divided into two main sections. Large Scale & Power Applications will include fusion and SMES, detectors and accelerators, fault current limiters, motors and generators, high magnetic fields, wires and cables, materials related to large-scale applications, system aspects, and other applications. Small Scale & Electronic Applications will include Josephson Junctions, SQUIDs, digital applications, mixers/detectors, passive devices, oscillators and volt standards, materials related to superconducting electronics, system aspects, and other applications. Abstract deadline, March 15, 1999. For further information, contact Xavier Obradors, Institut de Ciencia de Materials de Barcelona (ICMAB-CSIC), Campus de la UAB, E-08193 Bellaterra (Barcelona), Catalonia, Spain; phone +34 93 580 18 53; fax +34 93 580 57 29; e-mail eucas99@ icmab.es; Web site http://www.icmab.es/eucas99.

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

Position Available: A talented and resourceful experimentalist with a Ph.D. in physics is sought to fill a Postdoctoral Research Associate position at the University of Maryland. Work will involve development of quantum computers using superconducting devices. The ideal applicant will have experience with millikelvin techniques and the operation and fabrication of thin-film superconducting devices such as SQUIDs. A good understanding of quantum mechanics and the ability to lead graduate students is required. To apply, mail a hard-copy CV and the names of three references to Prof. C. J. Lobb, Center for Superconductivity Research, Department of Physics, University of Maryland, College Park, MD 20742-4111.

Position Available: A postdoctoral position is available at the Dipartimento di Scienze Fisiche "E.R. Caianiello," University of Salerno, Italy, to join a program of research on theoretical analysis of highly correlated electron systems. The applicant must have experience in methods of quantum field theory applied to condensed-matter physics, superconductivity, magnetism, and phenomenology of high-Tc cuprates. Programming experience in Fortran is required. Date of availability: January 1999 (negotiable); duration: one year, with a second-year extension possibility; salary: 20.000.000 Italian Lira per annum; job requirement: Ph.D. in condensed-matter physics; age requirement: must be younger than 32 years old. A formal application must be sent within one month to the Rector of the University of Salerno. Prospective candidates are invited to request formal application form, and send an informal application (including CV and list of publications) to Prof. F. Mancini, Dipartimento di Scienze Fisiche "E.R. Caianiello," Universita degli Studi di Salerno, Via S. Allende, I-84081 Baronissi (SA), Italy; telephone +39 089 965322; telefax +39 089 965275; e-mail mancini@vaxsa.csied.unisa.it.

Position Available: A two-year NRC Postdoctoral Research Associateship is available at the National Institute of Standards and Technology, Gaithersburg, Maryland. Position is open for the study of the magnetic structure of alloys, ferromagnetic resonance, magnetic domain imaging, Mossbauer effect spectroscopy, magnetic properties of high-Tc superconducting oxides, artificially modulated alloys, micromagnetic modeling, multicomponent nanocrystalline materials, and magnetic engineering. Candidates must be U.S. citizens and must have possessed a Ph.D. for less than five years at the time of application. Stipend: $48,500 + an annual allocation of $5,500. Application deadline, January 15, 1999; date of availability, September 1999. Contact Dr. Robert Shull, Leader, Magnetic Materials Group, National Institute of Standards and Technology, Gaithersburg, MD 20899-8552; telephone (301) 975-6035; e-mail robert.shull@nist.gov.

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Visit the High-Tc Update Web site at http://www.iitap.iastate.edu/htcu/htcu.html. You can find back issues of the newsletter and search through the issues for specific keywords or authors. You will also find several alternate formats of the newsletter and a complete listing of upcoming conferences. Let us know of other items you are interested in seeing at our Web site!

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. 12, #24, December 15, 1998.