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Vortices

For some time it has been known that the jump in resistance at the vortex lattice melting transition is a constant, independent of the magnetic field (vortex density). A preprint by A. G. Rojo (Michigan) et al. proposes an explanation of this effect based on vortex cutting and universality of the structure factor at the freezing transition (the Hansen-Verlet criterion).

Experiments probing transport along both the ab plane and the c axis in YBa2Cu3O7-d (YBCO) single crystals in a magnetic field H||c are reported by D. Lopez (IBM-Yorktown) et al. The authors found that at high fields point-like disorder destroys the c-axis coherence of vortex lines, so that the vortex matter can solidify in an entangled form at low temperatures. In untwinned YBCO single crystals above the critical point of the first-order melting transition, the authors found that the longitudinal dissipation is finite even where the transverse dissipation tends to zero, indicating large vortex-liquid pinning in the presence of significant vortex cutting and recombination.

A theoretical paper by B. Horovitz and T. R. Goldin (Ben-Gurion University of the Negev) examines phase transitions of a vortex lattice in layered superconductors with a magnetic field perpendicular to the layers and in the presence of disorder. As a function of the flux density B and temperature T, the authors found four phases, a Josephson glass (JG) at low B and T, a decoupled glass (G) at low T and high B, a depinned Josephson phase (J) at low B and high T, and a decoupled and depinned phase (D) at high B and high T. The boundaries between these phases intersect at a multicritical point where all four phases meet.

The influence of lowest-Landau-level (LLL) fluctuations near H_[c2](T) on vortex-lattice melting in YBa2Cu3O7-d (YBCO) has been investigated theoretically by S. W. Pierson (Worcester Polytechnic Institute) and O. T. Valls (Minnesota). The authors find that the specific-heat step of the vortex-lattice melting transition in YBCO single crystals can be attributed largely to the degrees of freedom associated with LLL fluctuations.

The London free energy and the tilt modulus of the vortex lattice in type-II superconductors have been calculated by A. M. Ettouhami (Colorado). The author points out why previous expressions for the tilt modulus c_[44](k) are incorrect. The new expression naturally obeys the limiting behavior c_[44](k=0) = BH/4[pi] required by thermodynamics.

A finite-temperature Monte Carlo study of the XY model in the vortex representation has been carried out by J. Lidmar (Royal Institute of Technology, Stockholm) et al. When magnetic-field fluctuations are neglected, corresponding to the absence of screening, the dynamical critical exponent of the vortex motion is found to be z ~~ 1.5. In the opposite limit, when magnetic-field fluctuations are taken into account in the strong-screening limit, the authors obtain z ~~ 2.7.

A transport study of the onset of the peak effect in a 2H-NbSe2 single crystal with very weak pinning has been carried out by X. S. Ling (Brown) et al. The authors found hysteresis, which they relate to the existence of two vortex-lattice phases, the Bragg glass (ordered) phase and the disordered phase.

Voltage jumps at high flux-flow velocities in the current-voltage characteristics of c-axis-oriented Bi2Sr2CaCu2O8+d (Bi-2212) superconducting thin films have been observed by Z. L. Xiao et al. (Mainz). The experimental results agree quantitatively with the theory of A. J. Bezuglyj and V. A. Shklovskij [Physica C 202, 234 (1992)], who accounted for self-heating effects in extending the theory of A. I. Larkin and Yu. N. Ovchinnikov [Sov. Phys. JETP 41, 960 (1976)]. The underlying theoretical explanation for the vortex instability is that the viscous drag force on a moving vortex initially increases linearly with the vortex speed v but reaches a maximum at a critical value v_[LO] and then decreases for speeds v > v_[LO].

A paper by N. B. Kopnin (Landau Institute and Helsinki University of Technology) predicts a resonant microwave absorption by collective vortex modes in a superclean d-wave superconductor at low temperatures. The energies of the collective modes are multiples of the distance between the exact quantum levels of bound states in the vortex core at lower temperatures and involve delocalized states for higher temperatures. The characteristic resonant frequency is larger than the cyclotron frequency omega_c but smaller than the Caroli-de Gennes- Matricon minigap Delta^2/E_F; it depends on magnetic field as H^[1/2] and decreases down to omega_c with increasing temperature.

The quasiparticle states associated with an isolated vortex in a d-wave superconductor have been investigated by M. Franz and Z. Tesanovic (Johns Hopkins) by numerically solving the Bogoliubov-de Gennes equations self-consistently. For a pure d_[x^2-y^2] superconductor, the authors find that core states are delocalized with tails extended along the gap node directions, the lowest state being near zero energy. This result is inconsistent with scanning tunneling spectroscopy data on vortices in YBa2Cu3O7-d, which show isotropic localized states with a large gap. The authors propose an explanation for the data in terms of a d_[x^2-y^2] + id_[xy] state, which recently has been invoked in connection with thermal conductivity measurements on Bi2Sr2CaCu2O8+d (Bi-2212).

The conversion of energy between longitudinal ultrasonic waves propagating perpendicular to the layers of a Bi2Sr2CaCu2O8+d (Bi-2212) single crystal and electromagnetic signals in a pick-up coil near the surface has been measured by H. Haneda (Kyoto) et al. as a function of the magnitude and direction of an applied dc magnetic field. The conversion efficiency is maximized when the applied magnetic field is nearly parallel to the layers, an effect the authors attribute to intrinsic pinning of vortices.

Theory

A preprint by I. Panas et al. (Goeteborg) examines the detailed electronic properties of cluster models via ab initio quantum chemistry. The authors use their results to explain why the cuprates are superconductors and the manganites are magnetoresistors: the metal band is orthogonal to the magnetic band in the cuprates, whereas it hybridizes with the magnetic centers in the manganites. A related paper by I. Panas (Goeteborg) uses cluster spectroscopy to explain the spin- flip resonances at 27, 33, and 40 meV for three different hole dopings in YBa2Cu3O6+x, observed by H. F. Fong et al. [Phys. Rev. Lett. 78, 713 (1997)]. The author notes that this approach is the antithesis of the Zhang-Rice singlet scenario.

A strong-coupling expansion for models of correlated electrons in any dimension has been developed by S. Pairault et al. (Sherbrooke). The authors apply the model to the one-dimensional Hubbard model and compare with numerical results. Third-order expansion of the Green function suffices to exhibit both the Mott metal-insulator transition and a low- temperature regime where antiferromagnetic correlations are strong. The authors predict that some of the weak photoemission signals observed in one-dimensional systems such as SrCuO2 should become stronger as temperature increases away from the spin-charge-separated state.

The physical nature of dimensional crossovers in weakly coupled Hubbard chains and ladders is discussed in a preprint by J.-I. Kishine and K. Yonemitsu (Okazaki) using the perturbative renormalization-group approach. The authors find that the difference in the universality classes of isolated chains and ladders profoundly affects the relevance of interchain or interladder one-particle hopping.

The response of an electron system that exhibits ideal nesting features has been investigated by D. Djajaputra and J. Ruvalds (Virginia). Using the Matsubara formalism, the authors derive analytic expressions for the real and imaginary parts of the bare particle-hole susceptibility. The imaginary part has sharp peaks whose maxima at the nesting momenta approximately scale with omega/T. The peak lineshapes resemble neutron- scattering data on chromium and some copper-oxide superconductors.

Although it is generally accepted that the fullerene superconductors can be understood in terms of phonon-mediated s-wave pairing, the NMR Hebel- Slichter coherence peak in the nuclear spin-lattice relaxation rate 1/T_1 just below Tc is strongly suppressed, and the origin of this suppression has not been established. A preprint by H.-Y. Choi (Sung Kyun Kwan University) explains this effect as arising from damping in the superconducting state induced by the Coulomb interaction between conduction electrons. The author models the Coulomb interaction in terms of the on-site Hubbard repulsion and incorporates this self- consistently into the Eliashberg theory at all temperatures on an equal footing with the electron-phonon interaction, with the vertex correction included via the method of Nambu.

RBa2Cu3O7-d

[63]^Cu NMR relaxation measurements in four oriented powders of YBa2Cu3O6+x are reported by P. Carretta (Pavia). Although the oxygen contents are different (0.57 and 0.67), the samples show similar Tc and [89]^Y NMR paramagnetic shifts, indicating a very similar hole doping of the Cu(2)O2 planes. However, the amplitude of the gap in the spin excitations derived from measurements of the [63]^Cu(2) nuclear spin- lattice relaxation rate 1/T_1 can vary by more than 60% from sample to sample. The results show that the ordering in the CuO chains can tune the amplitude of the spin gap.

Three papers by E. Sudhakar Reddy and T. Rajasekharan (Hyderabad) and one paper by E. Sudhakar Reddy (Hyderabad) et al. report on the properties of melt-textured GdBa2Cu3O7-d (Gd-123) containing various amounts of Gd2BaCuO5 (Gd-211). The authors report on the size and shape of the 211 particles as a function of the 211 content, and they discuss effects on the critical current density Jc. A related paper by E. Sudhakar Reddy and T. Rajasekharan reports that the cracks between the platelets in melt-processed RBa2Cu3O7-d superconductors develop during solidification and are not caused by cracking of larger platelets upon cooling after solidification.

Bi Cuprates

The partial melting behavior in electrophoretically deposited Bi2Sr2CaCu2O8+d/Ag tapes has been investigated by S.-L. Huang (Oxford and Trondheim) and D. Dew-Hughes (Oxford). The authors find that the partial melting initiates at a number of sites near the oxide/Ag interface and then spreads both across the broad surface and through the thickness. The initial partial melting temperature of Bi-2212 precursor powder depends on the intimacy of the contact between the Bi-2212 powder and the silver substrate.

The temperature dependence of the hysteretic energy losses in a polycrystalline (Bi,Pb)2Sr2Ca2Cu3O10+d [(Bi,Pb)-2223] superconductor has been studied by K. A. Ziq et al. (Dhahran). By measuring the saturated field-cooled hysteresis loops, the authors were able to separate the total energy loss into a diamagnetic surface contribution and a trapped- flux contribution.

The effects of 2223 phase content, grain morphology, texture, and core density upon the critical current in Ag-sheathed Bi-2223 tapes have been studied by P. Kovac (Bratislava) et al. Four tapes differing in thermomechanical treatment were analyzed structurally (XRD, EDX, SEM, and TEM), mechanically (microhardness), and electrically (transport I_c measurements in self field, I_c in externally applied fields up to 1.2 T, and dependence of I_c upon the angle of the applied magnetic field, all at 77 K). The authors point out difficulties in correlating the structural and electrical properties.

A preprint by M. Suenaga (Brookhaven) et al. reports a detailed comparison between values of the critical current density Jc in Bi- 2223/Ag tapes determined from standard four-probe dc measurements and from Bean-model fits to the ac losses measured using the magnetically induced current method. The authors found a significant inconsistency between the two values of Jc, particularly at high fields.

A modified version of the powder-in-tube method has been used by A. N. Iyer (TCSUH) et al. to fabricate Bi-2223/Ag tapes. In this method, the silver billet was reduced in size by groove rolling instead of wire drawing. Subsequent thermomechanical treatment to reduce crack formation resulted in tapes with a self-field, 77 K critical current density of 1.97 x 10^4 A/cm^2, corresponding to a critical current of about 40 A.

Other Cuprates

Polarized Raman measurements of the low-energy electronic continua of La1.78Sr0.22CuO4 have been carried out by J. G. Naeini (Simon Fraser) et al. over a wide range of temperatures. From the low-frequency B_[1g] spectra, the authors estimated the temperature-dependent scattering rate Gamma(T) for quasiparticles on portions of the Fermi surface near the (+-1,0) and (0,+-1) directions. The results appear to be in good agreement with the predictions of the nearly antiferromagnetic Fermi- liquid model, and in particular a crossover from a mean-field to a pseudoscaling behavior at T_[cr] ~~ 160 K is suggested. However, the authors found no evidence for a crossover to a pseudogap regime. This suggests that T* <= Tc for this overdoped sample.

Magnetization measurements of HgBa2CuO4+d (Hg-1201) microcrystals with different oxygen doping d have been carried out by J. Hofer (Universitaet Zurich and IBM-Zurich) et al. using a miniaturized torque sensor. The doping dependence of the effective mass anisotropy gamma = (m_c*/m_[ab]*)^[1/2] of the penetration depth lambda and coherence length xi was extracted from angular-dependent torque measurements. The anisotropy gamma was found to increase monotonically with decreasing d, suggesting a smooth 3D-2D crossover in the superconducting properties on reducing the oxygen content. The authors suggest that the increase of gamma may be due to an increase in the effective mass of the charge carriers, which in the framework of a bipolaronic model can be explained by an increase of the polaron binding energy with reduced doping.

The phonon density of states, lattice specific heat, and Debye temperature of HgBa2Ca2Cu3O8+d (Hg-1223) have been calculated by P. K. Jha (Barcelona) and S. P. Sanyal (Bhopal) using an unscreened rigid-ion model. The authors also compare the phonon density of states in Hg-1201 and Hg-1223 and point out similarities and differences.

The effect of Sn doping in (Hg1-xSnx)Ba2Ca2Cu3O8+d superconductors has been investigated by J. Q. Li et al. (Hong Kong). The results show that a small amount of Sn doped in Hg-1223 promotes the formation of the triple CuO2-layer superconducting compound and that the stability of the product is also enhanced. While the Tc for the Sn-doped samples with x <= 0.1 does not significantly change relative to that of the pure Hg- 1223 phase (about 134 K), further doping leads to a deterioration in Tc and the fraction of superconducting phase.

Preprints by N. M. Hamdan et al. (Dhahran) and A. S. Al-Harthi et al. (Dhahran) report enhancements of the superconducting properties of (Tl0.5Pb0.5)Sr1.6Ba0.4Cu3OyFx with fluorine doping. The authors found that F addition increased the superconducting transition temperature Tc to an optimum value (onset Tc = 128 K, zero-resistance Tc = 123 K) for one fluorine atom per formula unit (x =1).

Thin Films

As reported by M. Bauer et al. (TU-Muenchen), biaxially textured MgO buffer layers have been produced via e-gun evaporation on polycrystalline and amorphous substrates by inclining the substrate relative to the MgO vapor beam direction. The authors also studied the properties of YBCO films grown epitaxially on biaxially textured MgO buffer layers on polycrystalline YSZ. The critical current density of these films (up to 2.8 x 10^5 A/cm^2 at 77 K) was found to be considerably higher than those of films on polycrystalline substrates without the MgO buffer layer.

As shown theoretically by G. S. Lee (Hewlett-Packard, Palo Alto), Josephson tunneling from an s-wave superconductor into the c axis of a d_[x^2-y^2] superconductor can occur if multiple spin-orbit scattering occurs in the tunneling process. The author also notes that singlet s- wave to triplet p-wave coupling can always occur in the presence of spin-orbit scattering, as can singlet d-wave to triplet p-wave. The author suggests experiments by which the theory can be tested.

Applications

As pointed out by B. Zeimetz et al. (Wollongong), the heat leak of a normal-metal current lead cannot be reduced by tapering the lead because of the intimate coupling of the thermal and electrical resistivity via the Wiedemann-Franz law. Metallic leads are therefore usually made with constant cross section, and tapered leads have received little theoretical attention. However, in the case of high-temperature superconductor (HTS) leads, tapering can reduce the heat loss because of the strong Jc(T) dependence of the HTS. In their paper, Zeimetz et al. derive an analytical model for optimizing the length of a tapered current lead, and they give a general equation to calculate the heat leak. Numerical results obtained for different sheath alloys show that the optimum length is extremely sensitive to alloy composition.

The prospects for Peltier cooling of superconducting electronics are discussed by R. P. Huebener (Tuebingen) and C. C. Tsuei (IBM-Yorktown). The authors report on an experiment using a commercially available Peltier module in which the temperature at the warm end was fixed at 282 K by cooling water and the temperature at the cool end reached 149 K. The authors note that to cool below Tc of the cuprates, better thermoelectric materials are required. The authors discuss estimates of the figure of merit needed to achieve such temperatures in multistage Peltier systems.

Preprints by A. A. Kordyuk (Kiev) and A. A. Kordyuk (Kiev) et al. report experimental and theoretical studies of the magnetic levitation force between a superconductor and a permanent magnet. The authors discuss both viscous and hysteretic losses.

Variables affecting the magnetic levitation force between melt-textured YBCO superconductors and a permanent magnet have been studied by Y.-S. Lee (Sung Kyun Kwan University) et al. The authors report that the levitation force depends upon the cooling method, the crystal orientation, and the sample thickness of the superconductor, as well as reversals in the polarity of the permanent magnet.

Other Activities

A preprint by G. A. Levin (Kent State) et al. reports a study of the reduction of giant flux creep in high-temperature superconductors by the method of J. Z. Sun et al. [Science 247, 307 (1990)], in which the temperature T is temporarily increased above the operating temperature T_0 after the critical state is created at T_0. This T increase leads to a supercritical state, which decays rapidly, so that, when T is decreased back to T_0, the superconductor is in a subcritical state with a very low creep rate. The authors show that both the maximum persistent current and the relaxation rate are hysteretic and differ substantially from the corresponding quantities measured after flux annealing.

The current and magnetic-field distribution in a disk-shaped superconducting film has been calculated by X. N. Xu (Nanjing) et al. The authors consider the behavior when a magnetic field is applied parallel to the symmetry axis of a disk-shaped thin film of radius R and thickness d. Using cylindrical coordinates, a finite-element analysis, and matrix operations, the authors develop a method by which the field- dependent critical current Jc(B) can be obtained from magnetic-moment hysteresis measurements.

The diffusion of current into superconducting thin-film strips has been investigated theoretically and experimentally by Z. Y. Zeng (Nanjing) et al. The authors studied the time-dependent relaxation of electrical resistance.

Overviews

An introduction to the theory of matrix classical Green's functions has been prepared by A. F. Volkov (Lancaster and Moscow) and V. V. Pavlovskii (Moscow). The authors apply the theory to calculate the transport properties of mesoscopic superconducting/normal metal (S/N) structures. The authors also discuss (a) the subgap conductance in SIN tunnel junctions and (b) Josephson effects in four-terminal SNS structures (36 refs.).

An overview of growth mode issues in the heteroepitaxy of complex oxides is presented in a paper by B. Dam and B. Staeuble-Puempin (Amsterdam and Bogota). The authors use the growth of YBa2Cu3O7-d as an example, with an emphasis on films grown by pulsed laser deposition (PLD). Although a high density of antiphase boundaries and dislocations is found, this is an advantage for practical applications of high-Tc superconductors, since such defects act as strong pinning centers responsible for high critical currents (30 refs.).

Ph.D. Thesis

Three investigations in the theory of superconductivity are reported in the Illinois Ph.D. thesis of I. Kosztin: (a) nonlocal effects on the penetration depth in unconventional superconductors, (b) the free energy of an inhomogeneous superconductor using a wave-function approach, and (c) classical and quantum properties of Andreev billiards (138 refs.).

Contributed by John R. Clem

Contents: Preprints begin on page 5; Coming Events begin on page 11; Resources are on page 12; FYI begins on page 12; and Donors are on page 13.

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. Al-Harthi, N. M. Hamdan, and Kh. A. Ziq, "Fluorination of the Overdoped Tl-1223 Superconductor." Presented at the 10th Int. Symp. on Supercond. (ISS'97), Gifu, Japan, Oct. 27-30, 1997. Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261, SAUDI ARABIA; N. M. Hamdan's telephone +966 3 860 2255; telefax +966 3 860 2293; e-mail nmhamdan@dpc.kfupm.edu.sa. Key words: Tl-1223, F addition, critical temperature and critical currents, SEM.

Markus Bauer, Joachim Schwachulla, Joerg Egly, Paul Berberich, and Helmut Kinder, "Biaxially Aligned MgO Buffer Layers Using Electron Beam Evaporation on Inclined Substrates." Presented at the 10th Int. Symp. on Supercond. (ISS'97), Gifu, Japan, Oct. 27-30, 1997. Physics Department E10, Technical University of Muenchen, James-Franck-Str.1, D- 85747 Garching, GERMANY; telephone +49 89 2891 2419; telefax +49 89 2891 2414; e-mail mbauer@physik.fu-muenchen.de. Key words: MgO, YBCO, electron-beam evaporation, inclined-substrate deposition, biaxial texture.

P. Carretta, "NMR Evidence for the Influence of CuO Chains Ordering on the Opening of the Spin-Gap in YBa2Cu3O6+x." To be published in Physica C (in press). Department of Physics A. Volta, Unita INFM and Sezione INFN di Pavia, Via Bassi 6, I-27100 Pavia, ITALY; telephone +39 382 507465; telefax +39 382 507563; e-mail carretta@pavia.infn.it. 76.60.Es; 74.72.Bk; 74.20.Mn.

Han-Yong Choi, "Coulomb Suppression of NMR Coherence Peak in Fullerene Superconductors." Department of Physics, Sung Kyun Kwan University, Suwon 440-746, KOREA; e-mail hychoi@yurim.skku.ac.kr; preprint also available at cond-mat@xxx.lanl.gov (#9711060).

B. Dabrowski, K. Rogacki, Chong Zheng, and D. G. Hinks, "Single-Crystal Growth and Characterization of Zn- and Ni-Substituted YBa2Cu4O8." To be published in Physica C (in press). Department of Physics, Northern Illinois University, DeKalb, IL 60115; telephone (630) 252-5470; telefax (630) 252-7777.

B. Dam and B. Staeuble-Puempin, "Growth Mode Issues in Epitaxy of Complex Oxide Thin Films." Submitted to J. Mater. Sci. Institute COMPAS, Faculty of Physics and Astronomy, Vrije Universiteit, De Boelelaan 1081, NL-1081 HV Amsterdam, THE NETHERLANDS; e-mail dam@nat.vu.nl. Key words: epitaxy, growth mechanisms, surface diffusion, pulsed-laser deposition, spiral growth YBa2Cu3O7-d, high- temperature superconductors.

D. Djajaputra and J. Ruvalds, "Susceptibility and Vertex Corrections for a Square Fermi Surface." Department of Physics, University of Virginia, Charlottesville, VA 22903; telephone (804) 924-6796; telefax (804) 924- 4576; e-mail jr7k@virginia.edu.

Abdel Mouneim Ettouhami, "On the London Free Energy and Tilt Modulus of the Flux Line Lattice in Type II Superconductors." Department of Physics, University of Colorado, Boulder, CO 80309; e-mail mouneim@bogart.colorado.edu; preprint also available at cond- mat@xxx.lanl.gov (#9711199). 74.20.De; 74.60.Ge.

S. Friemel, C. Pasquier, and D. Jerome, "c-Axis Transport in the Intrinsically Layered Superconductor kappa-(BEDT-TTF)2Cu(NCS)2: Interplay Between Josephson and Quasiparticle Tunneling." To be published in Physica C (in press). Contact C. Pasquier, Laboratoire de Physique des Solides, Universite Paris-Sud, Batiment 510, F-91405 Orsay Cedex, FRANCE; telephone +33 1 69 155300; telefax +33 1 69 156086; e- mail pasquier@lps.u-psud.fr. Key words: organic superconductor, electrical resistivity, mixed state, Josephson effect. 74.70.Kn; 74.25.Fy; 74.50.+r.

Y. Ge, S. Y. Ding, Q. Ding, C. Ren, L. Qiu, F. Y. Ling, X. X. Yao, Y. X. Fu, and C. B. Cai, "Harmonic ac Susceptibilities for Textured YBa2Cu3O7." To be published in Physica C (in press). Contact S. Y. Ding, Department of Physics, National Laboratory of Solid State Microstructures, Nanjing University and Center for Advance Studies in Science and Technology of Microstructures, Nanjing 210093, PEOPLE'S REPUBLIC OF CHINA; telephone +86 25 359 4023; telefax +86 25 330 0535; e-mail syding@netra.nju.edu.cn.

Pijush K. Ghosh, N. Murali Krishna, and Keshav N. Shrivastava, "Viscous Damping Effect on the Magnetic Penetration Depth in Superconducting ErNi2B2C." Submitted to J. Phys. Cond. Mat. School of Physics, University of Hyderabad, P.O. Central University, Hyderabad 500 046, INDIA; Keshav N. Shrivastava's telephone +91 40 3010-227 or -500; telefax +91 40 3010-120 or -145; e-mail knssp@uohyd.ernet.in.

Sanjay Gupta, R. Suba, B. D. Padalia, Om Prakash, R. M. Nayak, I. K. Gopalakrishnan, and J. V. Yakhmi, "X-ray Absorption Spectroscopic Studies of the T+-Type Gd1.85-xPrxCe0.15CuOy System." To be published in Physica C (in press). Contact B. D. Padalia, Department of Physics, Indian Institute of Technology, Powai, Mumbai 400076, INDIA; telephone +91 22 578 2545; telefax +91 22 578 3480; e-mail phbdpia@niharika.phy.iitb.ernet.in.

J. Hagel, S. Wanka, D. Beckmann, J. Wosnitza, D. Schweitzer, W. Strunz, and M. Thumfart, "Vortex Dynamics of the Organic Superconductor kappa- (ET)2Cu[N(CN)2]Br." To be published in Physica C (in press). Contact J. Wosnitza, Physikalisches Institut, Universitaet Karlsruhe, D-76128 Karlsruhe, GERMANY; telephone +49 721 608 3515; telefax +49 721 608 6103; e-mail jochen.wosnitza@physik.uni-karlsruhe.de. 74.70.Kn; 74.60.- w.

N. M. Hamdan, Kh. A. Ziq, A. S. Al-Harthi, and J. Shirokoff, "The Effect of Fluorine on the Phase Formation and Properties of Tl-Based Superconductors." To be published in J. Supercond.: Proc. of the Int. Workshop on Tl- and Hg-Based Supercond. Mater., Cambridge, U.K., May 25- 28, 1997. Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261, SAUDI ARABIA; telephone +966 3 860 2255; telefax +966 3 860 2293; e-mail nmhamdan@dpc.kfupm.edu.sa. Key words: Tl-based superconductors, fluorine, structure.

Hideki Haneda, Takehiko Ishiguro, Satoshi Watauchi, Jun-ichi Shimoyama, and Kohji Kishio, "Intrinsic Pinning of the Josephson Vortex in a Two- Dimensional Superconductor Bi2Sr2CaCu2O8+d Studied Via the Conversion of Ultrasonic to Electromagnetic Waves." Department of Physics, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto 606-01, JAPAN. Key words: intrinsic pinning, Josephson vortex, two-dimensional superconductor, mutual conversion between electromagnetic waves and ultrasonic waves.

J. Hofer, J. Karpinski, M. Willemin, G. I. Meijer, E. M. Kopnin, R. Molinski, H. Schwer, C. Rossel, and H. Keller, "Doping Dependence of Superconducting Parameters in HgBa2CuO4+d Single Crystals." To be published in Physica C. Physik-Institut der Universitaet Zurich, Winterthurerstrasse 190, CH-8057 Zurich, SWITZERLAND; telephone +41 1 635 57 74; telefax +41 1 635 57 04; e-mail jhofer@physik-rzu.unizh.ch. Key words: doping-dependent anisotropy, magnetic torque, polaronic model, Hg-1201. 74.62.Dh; 74.25.Ha; 74.20.Mn; 74.72.Gr.

Kenneth Holmlund and Petter Minnhagen, "I-V Characteristics for 2D Superconductors from Simulations of the 2D Coulomb Gas: Density Dependence and Exponents." To be published in Physica C (in press). Contact Petter Minnhagen, Department of Theoretical Physics, Umea University, 901 87 Umea, SWEDEN; telephone +46 90 16 5940; telefax +46 90 16 9556; e-mail minnhagen@tp.umu.se. 05.40.+j; 75.40.Mg; 74.76.-w; 74.25.Fy.

Baruch Horovitz and T. Ruth Goldin, "Josephson Glass and Decoupling of Flux Lattices in Layered Superconductors." Department of Physics, Ben- Gurion University of the Negev, Beer-Sheva 84105, ISRAEL; e-mail baruch@bgumail.bgu.ac.il; preprint also available at cond- mat@xxx.lanl.gov (#9711194).

M. Q. Huang, L. Chen, T. Yang, J. C. Nie, P. J. Wu, and Z. X. Zhao, "A New Preparation Technique for YBa2Cu3O7 Bicrystal Junctions." To be published in Physica C (in press). National Laboratory for Superconductivity, Institute of Physics and Center for Condensed Matter Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100080, PEOPLE'S REPUBLIC OF CHINA; telefax +86 10 6256 8834.

Sun-Li Huang and David Dew-Hughes, "Non-Uniform Partial Melting and Effect of Oxide/Ag Contact on Partial Melting Behavior in Bi-2212/Silver Tapes." To be published in Physica C. Department of Physics, Norwegian University of Science and Technology, Sem Saelandsv. 9, N-7034 Trondheim, NORWAY; telephone +47 73593640; telefax +47 73593695; e-mail sunlih@phys.ntnu.no. Key words: partial melting, non-uniformity, Bi- 2212 tape, electrophoretic deposition, Bi-2212/Ag interface.

R. P. Huebener and C. C. Tsuei, "Prospects for Peltier Cooling of Superconducting Electronics." To be published in Cryogenics. Physikalisches Institut, Lehrstuhl Experimentalphysik II, Universitaet Tuebingen, Morgenstelle 14, D-72076 Tuebingen, GERMANY. Key words: Peltier cooling.

Y. Ishida, T. Kimura, K. Kakimoto, Y. Yamada, Z. Nakagawa, Y. Shiohara, and A. B. Sawaoka, "Liquid Phase Epitaxy of YBa2Cu3Ox on MgO Substrates with Seed Films." To be published in Physica C (in press). Materials and Structures Laboratory, Tokyo Institute of Technology, Nagatsuta 4259, Midori, Yokohama 226, JAPAN; telephone +81 3 3536 5711; telefax +81 3 3536 5705. Key words: liquid-phase epitaxy, Y123, seed film. 81.15.Lm; 81.10.-h; 61.50.Cj.

A. N. Iyer, S. Salib, C. Vipulanandan, K. Salama, and U. Balachandran, "Phase Development and Critical Current Density of Bi-2223 Tapes Fabricated by Groove Rolling." Preprint #97:157; submitted to 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.

Prafulla K. Jha and Sankar P. Sanyal, "Lattice Vibrations in HgBa2Ca2Cu3O8 High Temperature Superconductor." To be published in Physica B. Institut Jaume Almera, Consell Superior d'Investigacions Cientifiques (CSIC), Lluis Sole Sabaris s.n., E-08028 Barcelona, SPAIN; e-mail pjha@ija.csic.es. Key words: high-Tc superconductor, phonon density of states, specific heat, Debye temperature. 63.10.+a; 63.20.Dj; 25.40.Fq.

H. Jin, K. Q. Ruan, C. Y. Wang, J. Zuo, C. Y. Xu, L. Z. Cao, and Y. H. Zhang, "Ion Size Effect on the Charge Transfer and Raman Spectrum of the (Pb0.65Sr0.35)Sr2(R0.5Ca0.5)Cu2Oy Compound." To be published in Physica C (in press). Structure Research Laboratory, Academia Sinica, University of Science and Technology of China, Hefei, Anhui 230026, PEOPLE'S REPUBLIC OF CHINA. Key words: ion size effect, charge transfer, Pb-1212 compound, Raman scattering.

K. Kajantie, M. Karjalainen, M. Laine, and J. Peisa, "Three-Dimensional U(1) Gauge+Higgs Theory as an Effective Theory for Finite Temperature Phase Transitions." Preprint #CERN-TH/97-332. Theory Division, CERN, CH-1211 Geneve 23, SWITZERLAND; e-mail keijo.kajantie@cern.ch; preprint also available at hep-lat@xxx.lanl.gov (#9711048).

T. Karlemo, M. Karppinen, L. Niinistoe, J. Linden, and M. Lippmaa, "Annealing Characteristics and Calcium Doping Effects in the Superconducting Pb2CuSr2[Eu1-xCax]Cu2O8+d System." To be published in Physica C (in press). Laboratory of Inorganic and Analytical Chemistry, Helsinki University of Technology, P.O. Box 6100, FIN-02015 Helsinki, FINLAND; telephone +358 9 451 2595; telefax +358 9 462373; e-mail tarja.karlemo@hut.fi. Key words: annealing, kinetics, substitution effects, Mossbauer spectroscopy.

J. S. Kim and E. P. Kvam, "Study on the Possible Structural Transition in Nd2-xCexCuO4-d." To be published in Physica C (in press). Department of Materials Engineering, Seoul City University, Seoul 130- 743, SOUTH KOREA. Key words: structural phase transition, type-II superconductors, T-O transition, Nd-system superconductor.

Jun-ichiro Kishine and Kenji Yonemitsu, "One-Particle vs. Two-Particle Crossover in Weakly Coupled Hubbard Chains and Ladders: Perturbative Renormalization Group Approach." Department of Theoretical Studies, Institute for Molecular Science, Okazaki 444, JAPAN; telephone +81 564 55 7306; telefax +81 564 53 4660; e-mail kishine@ims.ac.jp; preprint also available at cond-mat@xxx.lanl.gov (#9711085). Key words: doped Hubbard ladders, dimensional crossover, spin gap, superconductivity, Tomonaga-Luttinger liquid, perturbative renormalization group.

Hijiri Kito, Shozo Ikeda, Shunji Takekawa, Hideki Abe, and Hideaki Kitazawa, "Identification of the New Intermetallic Compounds Y3Ni4B4C3 and Y1Ni1B1C1; Related Homologous Series (LnC)m(B-Ni2-B)n." To be published in Physica C (in press). Electrotechnical Laboratory (ETL), 1-1-4, Umezono, Tsukuba, Ibaraki 305, JAPAN; e-mail skito@etl.go.jp. Key words: intermetallic borocarbides, Y3Ni4B4C3, Y1Ni1B1C1, structural refinement, Rietveld analysis.

N. B. Kopnin, "Resonant Absorption at the Vortex-Core States in d-Wave Superconductors." Low Temperature Laboratory, Helsinki University of Technology, P.O. Box 2200, FIN-02015 HUT, FINLAND; e-mail kopnin@boojum.hut.fi; preprint also available at cond-mat@xxx.lanl.gov (#9711246). 74.60.Ge; 74.25.Jb; 74.25.Fy; 74.72.-h.

Alexander A. Kordyuk, "Magnetic Levitation for Hard Superconductors." To be published in J. Appl. Phys. (in press). Institute of Metal Physics, National Academy of Sciences of Ukraine, 36 Vernadsky str., Kyiv 252142, UKRAINE; telephone +380 44 444-9538 or -1005; telefax +380 44 444-2561; e-mail kord@imp.kiev.ua.

Alexander A. Kordyuk, Vladimir V. Nemoshkalenko, Roman V. Viznichenko, and Wolfgang Gawalek, "The Investigation of Magnetic Flux Dynamics in Bulk HTS with Levitation Techniques." To be published in Mater. Sci. Eng.: Proc. of the 3rd European Conf. on Appl. Supercond. (EUCAS'97), Veldhoven, The Netherlands, June 30-July 3, 1997. Institute of Metal Physics, National Academy of Sciences of Ukraine, 36 Vernadsky str., Kyiv 252142, UKRAINE; telephone +380 44 444-9538 or -1005; telefax +380 44 444-2561; e-mail kord@imp.kiev.ua.

Ioan Kosztin, "Topics in Theory of Superconductivity." Submitted as a Ph.D. thesis (University of Illinois at Urbana-Champaign). Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801.

I. M. Kotelyanskii, A. D. Mashtakov, and G. A. Ovsyannikov, "High-Tc Step-Edge Junctions: Problem of Reproducibility." Presented at the Third European Conf. on Appl. Supercond. (EUCAS'97), Veldhoven, The Netherlands, June 30-July 3, 1997. Institute of Radio Engineering and Electronics, Russian Academy of Sciences, 103907 Moscow, RUSSIA; e-mail gena@hitech.cplire.ru.

P. Kovac, C. J. Eastell, W. Pachla, I. Husek, H. Marciniak, C.R.M. Grovenor, and M. J. Goringe, "Structure and Current Transport Mechanisms in Bi(2223)/Ag Tapes." To be published in Physica C (in press). Institute of Electrical Engineering, Slovak Academy of Sciences, Dubravska Cesta 9, 842 39 Bratislava, SLOVAKIA; telefax +421 7 375816; e-mail elekkova@savba.savba.sk. Key words: critical current density, grain alignment (texturing), scanning electron microscopy, transmission electron microscopy, anisotropic superconductor, pinning force.

N. Murali Krishna, Lydia S. Lingam, P. K. Ghosh, and Keshav N. Shrivastava, "Effect of Current-Loop Sizes on the Para-Meissner Effect in Superconductors." Submitted to Physica C. School of Physics, University of Hyderabad, P.O. Central University, Hyderabad 500 046, INDIA; Keshav N. Shrivastava's telephone +91 40 3010-227 or -500; telefax +91 40 3010-120 or -145; e-mail knssp@uohyd.ernet.in.

B. Krunavakarn, P. Udomsamuthirun, S. Yoksan, I. Grosu, and M. Crisan, "The Gap-to-Tc Ratio of a Van Hove Superconductor." To be published in J. Supercond. Department of Physics, Chulalongkorn University, Bangkok 10330, THAILAND. Key words: gap-to-Tc ratio, Van Hove singularity.

Yu. E. Kuzovlev, "Thermally Induced Magnetic Vortex Nucleation Near the Surface of Type II Superconductor." To be published in Physica C (in press). Donetsk Physico-Technical Institute, Ukrainian Academy of Sciences, 340114 Donetsk, UKRAINE; telephone +380 622 550221; e-mail kuzovlev@gam.dipt.donetsk.ua.

G. S. Lee, "Multiple Spin-Orbit Scattering and Josephson Tunneling Between s-Wave and d-Wave Superconductors." To be published in Physica C (in press). Hewlett-Packard Laboratories, 3500 Deer Creek Road, Bldg. 26M, Palo Alto, CA 94303; telefax (415) 857-6241; e-mail glee@hplms2.hpl.hp.com. Key words: Josephson effect, d-wave superconductor, proximity effect, spin-orbit scattering. 74.50.+r; 74.72.Bk; 71.70.Ej.

Yi-Sung Lee, Hyun-Soon Park, Il-Hyun Kuk, Gye-Won Hong, and Chan-Joong Kim, "Levitation Force of Melt-Textured Single- and Multi-Domain YBaCuO Superconductors." To be published in Korean J. Mater. Res. Contact Chan-Joong Kim, Superconductivity Research Laboratory, Korea Atomic Energy Research Institute, P.O. Box 105, Yusung, Taejon 305-600, SOUTH KOREA; telephone +82 42 868 8908; telefax +82 42 862 5496; e-mail cjkim2@nanum.kaeri.re.kr.

G. A. Levin, C. C. Almasan, D. A. Gajewski, and M. B. Maple, "Reduction of Flux Creep by Heat Pulses." Contact C. C. Almasan, Department of Physics, Kent State University, Kent, OH 44242; telephone (330) 672- 2402; telefax (330) 672-2959; e-mail calmasan@physics.kent.edu. Key words: electricity and magnetism, superconductivity.

J. Q. Li, C. C. Lam, J. Feng, and K. C. Hung, "Effects of Sn Doping in Hg1-xSnxBa2Ca2Cu3O8+d Superconductors." To be published in Physica C (in press). Contact C. C. Lam, Department of Physics and Materials Science, City University of Hong Kong, Hong Kong, PEOPLE'S REPUBLIC OF CHINA; telephone +852 2788 7831; telefax +852 2788 7830; e-mail apcclam@cityu.edu.hk. Key words: tin doping, Hg-based oxide superconductor, critical temperature.

Jack Lidmar, Mats Wallin, Carsten Wengel, S. M. Girvin , and A. P. Young, "Dynamical Universality Classes of the Superconducting Phase Transition." Submitted to Phys. Rev. B. Department of Theoretical Physics, Royal Institute of Technology, SE-100 44 Stockholm, SWEDEN; S. M. Girvin's e-mail at Indiana University smg@bardeen.physics.indiana.edu; preprint also available at cond- mat@xxx.lanl.gov (#9711236). 74.60.-w; 75.40.Mg; 05.70.Fh.

X. S. Ling, J. E. Berger, and D. E. Prober, "Nature of Vortex Lattice Disordering at the Onset of the Peak Effect." To be published in Phys. Rev. B. Department of Physics, Brown University, Providence, RI 02912; e-mail xsling@brown.edu. 74.60.Ge; 64.60.Cn.

Gennadii Yu. Logvenov, Paul Mueller, Mark V. Kartsovnik, and Harald Mueller, "Interlayer Resistance and Thermoelectric Power as a Probe of the Josephson Coupling in Layered Superconductors." To be published in Physica C (in press). Physikalisches Institut III, Universitaet Erlangen-Nuernberg, D-91058 Erlangen, GERMANY; telephone +49 9131 85 7082; telefax +49 9131 15249; e-mail logvenov@physik.uni-erlangen.de. Key words: layered superconductors, thermoelectric power, interlayer resistance, Josephson coupling. 74.70.-b; 74.70.Kn; 74.50.+r; 74.60.Ge; 74.80.Dm.

D. Lopez, L. Krusin-Elbaum, H. Safar, E. Righi, F. de la Cruz, S. Grigera, C. Feild, W. K. Kwok, L. Paulius, and G. W. Crabtree, "Pinned Vortex Liquid Above the Critical Point of the First-Order Melting Transition: A Consequence of Point-Like Disorder." To be published in Phys. Rev. Lett. IBM Thomas J. Watson Research Center, P.O. Box 218, Yorktown Heights, NY 10598.

A. W. McConnell, T. Timusk, A. Dabkowski, and H. A. Dabkowska, "Temperature Dependence of the FIR Reflectance of LaSrGaO4." To be published in Physica C (in press). Department of Physics, Simon Fraser University, Burnaby, B.C., CANADA V5A 1S6; telephone (604) 291-4843; telefax (604) 291-3592. Key words: LaSrGaO4, thin film substrate, optical reflectivity, far-infrared spectra, phonon spectrum. 78.30.-j.

A. V. Mitin, G. M. Kuz'micheva, and S. I. Novikova, "The Manganese-Based Complex Oxides with Perovskite Structure and Derivative from the Its." To be published in Zh. Neorgan. Khimii. Contact G. M. Kuz'micheva, Department of Solid State Physics and Chemistry, State M.V. Lomonosov Academy of Fine Chemical Technology, 86 pr. Vernadsky, Moscow 117571, RUSSIA; telephone +7 095 248 0762; e-mail kuz7micheva@glasnet.ru or alekz@cs.msu.su.

J. G. Naeini, X. K. Chen, K. C. Hewitt, J. C. Irwin, T. P. Devereaux, M. Okuya, T. Kimura, and K. Kishio, "Evidence for Magnetic Pseudoscaling in Overdoped La2-xSrxCuO4." Submitted to Phys. Rev. B. Department of Physics, Simon Fraser University, Burnaby, B.C., CANADA V5A 1S6; telephone (604) 291-5488; telefax (604) 291-3592; e-mail gharavi@sfu.ca; preprint also available at cond-mat@xxx.lanl.gov (#9711272). 74.25.Gz; 74.72.Dn; 74.25.-q; 78.30.Er.

Stephane Pairault, David Senechal, and A.-M.S. Tremblay, "Strong- Coupling Expansion for the Hubbard Model." Preprint #CRPS-97-25. Departement de Physique and Centre de Recherche en Physique du Solide, Universite de Sherbrooke, Sherbrooke, Quebec, CANADA J1K 2R1; preprint also available at cond-mat@xxx.lanl.gov (#9710256).

Itai Panas, "Possible Resolution of Superconductivity Induced Anomalies in the Spin-Excitation Spectra in YBa2Cu3O6+x." Department of Inorganic Chemistry, Goeteborg University, Kemivaegen 10, S-412 96 Goeteborg, SWEDEN; e-mail itai@inoc.chalmers.se.

Itai Panas, Refael Gatt, and Tobias Johnson, "High-Tc SC and CMR made Chemically Intuitive." To be published in J. Phys. Chem. Mater. Department of Inorganic Chemistry, Goeteborg University, Kemivaegen 10, S-412 96 Goeteborg, SWEDEN; e-mail itai@inoc.chalmers.se.

Stephen W. Pierson and Oriol T. Valls, "Flux Lattice Melting and Lowest Landau Level Fluctuations." Department of Physics, Worcester Polytechnic Institute (WPI), Worcester, MA 01609-2280; e-mail pierson@wpi.edu; Web site http://www.wpi.edu/~pierson/pubs.html; preprint also available at cond-mat@xxx.lanl.gov (#9711254). 74.25.Bt; 74.40.+k; 74.60.Ge.

J. Rao and T. Morishita, "Determination of the Surface Layer of Laser Ablated YBCO by Glancing Incident-Exit X-Ray Diffuse Scattering." To be published in Physica C (in press). Superconductivity Research Laboratory, International Superconductivity Technology Center (ISTEC), 10-13 Shinonome 1-chome, Koto-ku, Tokyo 135, JAPAN; telephone +81 3 3536 5703; telefax +81 3 3536 5714; e-mail rao@istec.or.jp. Key words: glancing incident x-rays, surface characterization, laser ablation, RHEED, CuO.

E. Sudhakar Reddy and T. Rajasekharan, "Effect of Gd2BaCuO5 Content on the Macro-Defect Structure of Melt Processed GdBa2Cu3Oy Superconductor." To be published in Supercond. Sci. & Technol. SSP Group, Tata Institute of Fundamental Research (TIFR), Homi Bhabha Road, Colaba, Mumbai 400 005, INDIA; telefax +91 22 215-2110 or -2181; e-mail esreddy@tifrvax.tifr.res.in. Key words: shrinkage, cracks, pores, melt processing, macro-defects, GdBa2Cu3Oy composites.

E. Sudhakar Reddy and T. Rajasekharan, "Fabrication of Textured REBa2Cu3O7/RE2BaCuO5 (RE=Y,Gd) Composites by Infiltration and Growth of RE2BaCuO5 Preforms by Liquid Phases." To be published in Supercond. Sci. & Technol. SSP Group, Tata Institute of Fundamental Research (TIFR), Homi Bhabha Road, Colaba, Mumbai 400 005, INDIA; telefax +91 22 215-2110 or -2181; e-mail esreddy@tifrvax.tifr.res.in. Key words: IG process, near-net processing, REBa2Cu3O7, superconductor composites.

E. Sudhakar Reddy and T. Rajasekharan, "Microstructural Studies of PrBa2Cu3Oy During Melt Processing." Submitted to J. Mater. Res. SSP Group, Tata Institute of Fundamental Research (TIFR), Homi Bhabha Road, Colaba, Mumbai 400 005, INDIA; telefax +91 22 215-2110 or -2181; e-mail esreddy@tifrvax.tifr.res.in. Key words: melt processing, PrBa2Cu3Oy , pro-peritectic phase, platelets, domains.

E. Sudhakar Reddy and T. Rajasekharan, "On the Characteristics of Peritectic Gd2BaCuO5 at the Pro-Peritectic Stage with Increasing Amounts of External Gd2BaCuO5." To be published in Mater. Lett. SSP Group, Tata Institute of Fundamental Research (TIFR), Homi Bhabha Road, Colaba, Mumbai 400 005, INDIA; telefax +91 22 215-2110 or -2181; e-mail esreddy@tifrvax.tifr.res.in. Key words: Gd2BaCuO5, pro-peritectic stage, nucleating substrates, refining, melt processing.

E. Sudhakar Reddy and T. Rajasekharan, "On the Gaps Between the Platelets in Melt Processed REBa2Cu3O7 Superconductors." To be published in Phys. Rev. B. SSP Group, Tata Institute of Fundamental Research (TIFR), Homi Bhabha Road, Colaba, Mumbai 400 005, INDIA; telefax +91 22 215-2110 or -2181; e-mail esreddy@tifrvax.tifr.res.in. Key words: platelets, gaps, microstructure, melt growth, REBa2Cu3O7. 74.72.Bk; 74.80.Bj; 74.60.Jg; 81.30.Fb.

E. Sudhakar Reddy, T. Rajasekharan, G. Ravikumar, V. Chandrasekhar Rao, and V. C. Sahni, "Microstructure and Magnetic Properties of Melt Processed GdBa2Cu3Oy with Varying Amounts of Gd2BaCuO5 Superconductors." To be published in Phys. Rev. B. SSP Group, Tata Institute of Fundamental Research (TIFR), Homi Bhabha Road, Colaba, Mumbai 400 005, INDIA; telefax +91 22 215-2110 or -2181; e-mail esreddy@tifrvax.tifr.res.in. Key words: microstructure, current densities, melt growth, GdBa2Cu3O7 composites. 74.72.Bk; 74.80.Bj; 74.60.Jg; 81.30.Fb.

A. G. Rojo, A. K. Sood, and C. A. Balseiro, "Universalities in Vortex Transport at the Melting Transition." Department of Physics, University of Michigan, Ann Arbor, MI 48109-1120; e-mail rojo@maradona.physics.lsa.umich.edu; preprint also available at cond- mat@xxx.lanl.gov (#9712017). 47.32.Cc; 64.70.Dv; 74.60.Ge.

H. Salamati, F. S. Razavi, and G. Quirion, "Effect of Pressure on the Superconductivity of ZrRuP." To be published in Physica C (in press). Contact F. S. Razavi, Department of Physics, Brock University, St. Catharines, Ontario, CANADA L2S 3A1; telephone (905) 688-5550; telefax (905) 682-9020; e-mail saar@newton.physics.brocku.ca.

S. Salib, A. N. Iyer, C. Vipulanandan, K. Salama, and U. Balachandran, "Electromechanical Characterization of Silver-Clad BSCCO Tapes." Preprint #97:156; submitted to 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.

Hiroyuki Sasakura, "New Members of Sr-Free Bi-2201 Cuprates: Bi2(La,A)2CuOz (A=Na and K)." To be published in Physica C (in press). Department of Physics, Hamamatsu University School of Medicine, Handa- cho, Hamamatsu, Shizuoka 431-31, JAPAN; telefax +81 53 4352315; e-mail sasakura@hama-med.ac.jp. Key words: Bi2(La,A)2CuOz (A=Na and K), 2201 phase, x-ray diffraction, electrical resistivity, magnetic susceptibility.

D. P. Scarfe, X. Z. Xiong, W. J. Zhu, P. H. Hor, S. C. Moss, and A. J. Jacobson, "Electrochemical Synthesis and Characterization of La2CuO4+d Single Crystals." Preprint #97:151; 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.

Elsebeth Schroeder and Ola Toernkvist, "Towards a Strong Formulation of Vortex Dynamics." Preprint #DAMTP-97-133; to be published in the Proc. of the Int. Workshop on Solitons, Their Properties, Dynamics, Interactions, and Applications in Kingston, Ontario, Canada, July 20-26, 1997. Physikalisches Institut der Universitaet Bayreuth, D-95440 Bayreuth, GERMANY; e-mail schroder@nbi.dk; preprint also available at hep-th@xxx.lanl.gov (#9711195).

A.P.B. Sinha, K. K. Singh, and D. E. Morris, "123 + CuO --> 124 Conversion Slowed by Lanthanum Substitution." To be published in Physica C (in press). Contact D. E. Morris, Morris Research, Inc., 44 Marguerita Road, Kensington, CA 94707; telephone (510) 525-0122; telefax (510) 525-8131.

H. Srikanth, S. Sridhar, D. A. Gajewski, and M. B. Maple, "Microwave Properties of (PrxY1-x)Ba2Cu3O7-d: Influence of Magnetic Scattering." To be published in Physica C (in press). Department of Physics, Northeastern University, 360 Huntington Avenue, Boston, MA 02115; telephone (617) 373-2948; telefax (617) 373-2943; e-mail srikanth@neu.edu; preprint also available at cond-mat@xxx.lanl.gov (#9709232). Key words: microwave absorption, penetration depth, pair breaking.

M. Suenaga, T. Chiba, H. J. Wiesmann, and P. Haldar, "The Bean Model and ac Losses in Bi2Ca2Cu3O10/Ag Tapes." Presented at the 10th Int. Symp. on Supercond. (ISS'97), Gifu, Japan, Oct. 27-30, 1997. Department of Applied Science, Brookhaven National Laboratory, Upton, NY 11973. Key words: power frequency ac losses, the Bean model, Bi2Sr2Ca2Cu3O10/Ag tapes.

J. J. Sun, B. R. Zhao, L. Li, B. Xu, J. W. Li, S. Q. Guo, and B. Yin, "Magnetization Relaxation and Vortex Activation Energy in YBa2Cu3O7/PrBa2Cu3O7 Multilayers." To be published in Physica C (in press). Contact B. R. Zhao, National Laboratory for Superconductivity, Institute of Physics and Center for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100080, PEOPLE'S REPUBLIC OF CHINA. Key words: magnetization relaxation, flux creep, collective pinning, multilayers. 74.76.Bz; 74.80.Dm; 74.25.Ha; 74.60.Ge.

A. Tsukamoto, J. G. Wen, K. Nakanishi, and K. Tanabe, "Growth and Ozone Oxidation of the SrCuO2/CaCuO2 Superlattices." To be published in Physica C (in press). Advanced Research Laboratory, Hitachi, Ltd., 1- 280 Higashi-Koigakubo, Kokubunji, Tokyo 185, JAPAN; telephone +81 423 23 1111; telefax +81 423 27 7722; e-mail tsukamoto@crl.hitachi.co.jp.

N. A. Tulina, "Point-Contact Investigations of the Resistive Properties of the Normal Metal-High Temperature Superconductor Boundary." To be published in Physica C (in press). Institute of Solid State Physics of Russian Academy of Science, 142432 Chernogolovka, Moscow District, RUSSIA; e-mail tulina@issp.ac.ru.

T. A. Tyson, J. F. Federici, D. Chew, A. R. Bishop, L. Furenlid, W. Savin, and W. Wilber, "Local Structural and Electronic Changes Accompanying Photodoping in YBa2Cu3O6+x." To be published in Physica C (in press). Department of Physics, New Jersey Institute of Technology, Newark, NJ 07102; telephone (201) 642-4681; telefax (201) 596-5794. Key words: XAFS, structure of photodoping, Cu-O chains, Cu-O planes.

A. F. Volkov and V. V. Pavlovskii, "Methods of Quasiclassical Green's Functions in the Theory of Transport Phenomena in Superconducting Mesoscopic Structures." Presented at Euroschool '97 on Superconducting Networks and Mesoscopic Structures (Sienna, Italy, 1997). School of Physics and Chemistry, Lancaster University, Lancaster LA1 4YB, UNITED KINGDOM; e-mail a.volkov@lancaster.ac.uk; preprint also available at cond-mat@xxx.lanl.gov (#9711251).

X. S. Wu, S. S. Jiang, W. M. Chen, J. Lin, and X. Jin, "Structural Changes of LaBa2Cu3-yFeyOx Cuprates with 0.0 <= y <= 0.50." To be published in Physica C (in press). National Laboratory of Solid State Microstructures, Institute of Solid State Physics, Nanjing University, and Center for Advanced Studies in Science and Technology of Microstructures, Nanjing University, Nanjing 210093, PEOPLE'S REPUBLIC OF CHINA. Key words: LaBa2Cu3Ox cuprate, iron doping, BaCuO2 impurity phase, phase transition.

Z. L. Xiao, P. Voss-de Haan, G. Jakob, and H. Adrian, "Voltage Jumps in Current-Voltage Characteristics of Bi2Sr2CaCu2O8+d Superconducting Films: Evidence for Flux-Flow Instability Under the Influence of Self Heating." To be published in Phys. Rev. B. Department of Physics & Astronomy, Rutgers University, Piscataway, NJ 08855; telefax (908) 445- 4343; e-mail eandrei@physics.rutgers.edu. 74.25.Fy; 74.60.Ge; 74.76.Bz.

X. N. Xu, A. M. Sun, M. J. Qin, S. Y. Ding, X. Jin, X. X. Yao, and S. L. Yan, "Current and Magnetic Field Distribution of Disk-Shaped Superconducting Film." To be published in Physica C (in press). Department of Physics and Center of Advanced Studies in Science and Technology of Microstructures, Nanjing University, Nanjing 210093, PEOPLE'S REPUBLIC OF CHINA; e-mail postphys@nju.edu.cn.

Y. Yu, Z. Y. Zheng, M. J. Qin, X. X. Yao, L. P. Ma, H. C. Li, and L. Li, "Characteristic Exponents Near Vortex-Glass Temperature in GdBa2Ca3Cu7-d Film." To be published in Physica C (in press). Department of Physics and Laboratory of Microstructure of Solid States, Nanjing University, P.O. Box 2020, Nanjing 210093, PEOPLE'S REPUBLIC OF CHINA; e-mail scmb@nju.edu.cn. 74.60.Ge; 74.60.Jg.

B. Zeimetz, H. K. Liu, and S. X. Dou, "General Design Formula for Tapered, Conduction-Cooled Current Lead Utilizing High Temperature Superconducting Tapes." Submitted to Cryogenics. Centre for Superconducting and Electronic Materials, University of Wollongong, Wollongong NSW 2522, AUSTRALIA; telephone +61 2 4221 5766; telefax +61 2 4221 5731; e-mail bpz01@uow.edu.au.

Z. Y. Zeng, X. X. Yao, M. J. Qin, Y. Ge, C. Ren, S. Y. Ding, L. P. Ma, H. C. Li, and L. Li, "Resistance Relaxation Resulting from Current Diffusion in Superconducting Thin Films." To be published in Physica C (in press). Department of Physics, National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, PEOPLE'S REPUBLIC OF CHINA; e-mail scmb@nju.edu.cn.

Kh. A. Ziq, N. M. Hamdan, and A. S. Al-Harthi, "Temperature Dependence of the Magnetic Energy Losses in a (Bi,Pb)2Sr2Ca2Cu3O10-d High Tc Superconductor." Presented at the 10th Int. Symp. on Supercond. (ISS'97), Gifu, Japan, Oct. 27-30, 1997. Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261, SAUDI ARABIA; N. M. Hamdan's telephone +966 3 860 2255; telefax +966 3 860 2293; e- mail c-nmhamdan@dpc.kfupm.edu.sa. Key words: Bi-2223, energy losses, field cooled, hystersis.

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

Jan. 7 - 10, 1998: Winter Workshop: In-Situ Electron Microscopy, Embassy Suites Resort, Scottsdale, Ariz. Goal is to provide a forum for presentation and discussion of recent developments in instrumentation, current applications, and future directions of in-situ electron microscopy. Some areas of interest are in-situ heating experiments, ion-implantation studies and ion-irradiation effects, controlled atmosphere TEM/SEM, effects of stress/strain including fracture studies and stress-induced phase transformation, and magnetic-materials studies. Invited and contributed papers, and posters. Participation is limited to about 100 persons. Most presentations will be published in a special issue of an archival journal. For further information, contact Eloise Kadri, Center for Solid State Science, Arizona State University, Box 871704, Tempe, AZ 85287-1704; telephone (602) 965-4424; telefax (602) 965-9004; e-mail eloise.kadri@asu.edu.

Jan. 12 - 16, 1998: 1998 Winter School on High Resolution Electron Microscopy, Arizona State University, Tempe, Ariz. Organized by Center for High Resolution Electron Microscopy, Center for Solid State Science, and Arizona State University. Aim of the school is to introduce the theory and practice of high-resolution electron microscopy to scientists currently using transmission electron microscopes for materials-science studies. Familiarity with basic crystallography, diffraction contrast, and routine microscope operation is assumed. Lecture topics are as follows: fundamentals of HREM, imaging theory, transfer functions in HREM, dynamical diffraction, diffractogram analysis, practical HREM operation, techniques for image calculation, convergent-beam microdiffraction, EELS and EDXS as complimentary techniques, radiation effects, applications to materials science and solid-state chemistry, and introduction to electron holography. Demonstrations of energy- filtered imaging, electron holography, STEM and microdiffraction, and techniques of specimen preparation will be scheduled for Jan. 16. For information, contact Eloise Kadri, Center for Solid State Science, Arizona State University, Box 871704, Tempe, AZ 85287-1704; telephone (602) 965-4424 telefax (602) 965-9004; e-mail eloise.kadri@asu.edu.

July 12 - 15, 1998: 1998 International Workshop on Superconductivity: Materials and Technology Issues for HTS Wires and Bulk Applications, Okinawa Harborview Hotel, Naha-shi, Okinawa, Japan. Workshop will focus on high-temperature superconductors in all forms. Topics of interest are: physics and characterization of HTS bulks, wires, and tapes; crystal growth and processing of HTS bulks, wires, and tapes; applications; flux pinning and flux dynamics; ac losses; and novel materials. A significant amount of time will be allotted for discussion of each paper, and extra time will be set aside for informal interactions among the participants. No parallel sessions. Abstract deadline, February 6, 1998. For information, contact Tetsuji Kobayashi, Superconductivity Research Laboratory, International Superconductivity Technology Center (ISTEC),10-13 Shinonome 1-chome, Koto-ku, Tokyo 135, JAPAN; telephone +81 3 3431 4002; telefax +81 3 3431 4044; e-mail funa@istec.or.jp.

July 18 - 26, 1998: 4th International Summer School on High Temperature Superconductivity, Eger, Hungary. Organized by Hungarian Chapter of Superconductivity Society. Objective is to provide an overview on the basic and up-to-date information on theories and newest results both in fundamental research and applications of high-temperature superconductors. The main frame of the Summer School is a series of tutorial lectures by well-known scientists. Round-table sessions to be organized to provide time for free discussions. Topics are: the second ten years of high-temperature superconductivity, survey of theories on high-Tc superconductivity, physical properties of high-Tc materials, characterization and measurements of the physical properties, new trends in preparation techniques, crystal structure of high-Tc materials, manufacturing of high-Tc conductors, and small- and large-scale applications. Last two days will be devoted to a scientific conference where participants can present results of their own work. Oral and poster presentations will be selected by the Local Organizing Committee. Papers to be published in the Proceedings of the Summer School. Abstract deadline, March 1, 1998. Scientific correspondence is to be addressed to Istvan Vajda, Department of Electrical Machines and Drives, Technical University of Budapest, H-1111 Budapest, Egry Jozsef u. 18., Hungary; telephone +36 1 463 2961; telefax +36 1 463 3600; e-mail vajda@ntb.bme.hu; Web site http://docs4.mht.bme.hu/~farkas/. For other matters, contact Attila Varga or Klara Langthe, Conference Secretariat, Diamond Congress Ltd., H-1255 Budapest, P.O. Box 48, Hungary or H-1027 Budapest, Fo u. 68., Hungary; telephone +36 1 214 7701; telefax +36 1 201 6383; e-mail diamond.eft@mtesz.hu.

RESOURCES

Information

New Book: Why Things Ae the Way They Are, by B. S. Chandrasekhar. The book explains in a completely nontechnical style how properties of materials result from the way they are composed of atoms, and addresses questions such as why copper and rubies are colored, why metals conduct heat better than glass, and how superconductors conduct electricity without resistance. Intended for the general reader. Chapters are: preface, introduction, crystals, particles and waves, the atom, statistical physics, the quantum mechanical crystal, copper wires and glass rods, silver spoons and plastic spoons, glass panes and aluminum foils, electric bulbs and insulated cables, magnets, and superconductors. Publ. 1997; 272 pp.; price $59.95 (HB) or $24.95 (PB); ISBN 45039-X or 45660-6. Contact Cambridge University Press, Orders Department, 110 Midland Avenue, Port Chester, NY 10573.

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

Positions Available: Two staff scientist positions (levels AD-2 and AD- 3) are open at the National Science Foundation, Office of Inspector General. Primary responsibilities include investigating allegations of misconduct in science and engineering, and participating in inspections. Applicants must possess a Ph.D. (or equivalent professional experience) in the biological sciences, computer sciences, science education, engineering, mathematical sciences, physical sciences, or social sciences; demonstrate a broad understanding of the practices of scientific and engineering research or education across disciplines; and possess excellent analytical and technical writing skills. AD-3 applicants must also have 4 years of successful research, education or research administration, and/or managerial experience. Salary range: $38,330 to $86,059. For application information call (703) 306-1185, ext. 3034, or visit the NSF Web site at http://www.nsf.gov/oirm/.

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High-Tc Update, Vol. 12, #1, January 1, 1998.