Published for the Division of Materials Sciences, Office of Basic Energy Sciences, USDOE, under Contract W-7405-eng-82 with the Ames Laboratory, Iowa State University. Funded by DMS/BES/USDOE, ARPA, NSF, and other agencies, organizations, and individuals.

The High-Tc Update web page is located at the URL http://www.iitap.iastate.edu/htcu/htcu.html

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

PLEASE READ: The electronic-mail version of High-Tc Update is generated from a Macintosh Microsoft Word file and turned into a text file that can be transferred electronically. Formatting commands, Greek symbols, diacritical marks, etc. are lost in this transformation. In order to improve the readability of the e-mail version, the newsletter staff add explanatory marks as needed to the text file. For example, a carat (10^5) indicates a superscript (ten to the fifth). A carat followed by a bracket (cm^[-2]) indicates everything within the brackets is superscripted (centimeter to the minus 2). A bracket followed by a carat ([18]^O) indicates everything before the carat is superscripted. An underline (M_i) indicates a subscript (M subscript i). Most Greek letters are spelled out (Delta, mu, tau, pi, Omega), although delta is left as "d." In most instances, easily recognizable formulas or units are left as they appear: Tc, Jc, YBa2Cu3O7, O2. Mu-m is changed to micrometers. Diacritical marks (accents, tildes, carats, etc.) are removed, but the German umlaut (e.g., a, o, or u with two dots over it) is changed into a, o, or u followed by e. If needed for clarity, hyphens are occasionally inserted between spelled-out Greek letters or symbols (ohm-cm, sin-theta).

NOTA BENE:

In the January 19, 1998, Newsweek is an article by Thomas Hayden with the headline "The Questions That Stump The Scientists." High- temperature superconductors is one of the six items listed, and the article asserts, "there still isn't a theory that can explain why it happens."

Correction: In the January 15 Nota Bene, we mentioned a report by Y. Abe et al. (Nagoya) that melt-quenched materials in the Bi-Sr-Ca-Cu-O system crawl at an extraordinarily high speed up the wall of a metallic copper vessel when the vessel filled with the cast materials is reheated at high temperatures around 850^oC in air. We should have said that the compositions for which this phenomenon was found to occur are those around Bi2Sr2CaCu2Ox (Bi-2212) and Bi2Sr2CaOx (Bi-2210), not Bi-2201.

Pseudogap

The widespread reference to phase diagrams for the high-Tc superconductors that involve two crossover temperatures T* and T_[cr] at temperatures above Tc in the underdoped normal-state region (Tc < T* < T_[cr]) has been critically examined by G.V.M. Williams (IRL, Lower Hutt) et al. The authors conclude that in both the q = (0,0) and the q = (pi,pi) response, there is only one crossover temperature (T_[cr]), best described as the pseudogap energy scale rather than a well-defined onset temperature. T_[cr] has a strong, linearly decreasing dependence on the hole concentration p. The authors show that the so-called lower crossover temperature T*, commonly determined from the [63]^Cu nuclear spin-lattice relaxation rate [63]^(1/T_1T), is merely an artifact of convoluting the pseudogap energy scale with an intrinsic linear T dependence, arising from the characteristic spin-fluctuation frequency omega_[sf](T) in the nearly antiferromagnetic Fermi-liquid (NAFL) model. The authors conclude that models constructed on the basis of the two- crossover-temperature scenario need to be re-examined.

Measurements of the doping dependence of the planar [63]^Cu Knight shift, the nuclear spin-lattice relaxation rate [63]^(1/T_1T), and the Gaussian spin-echo decay rate [63]^(1/T_G) are reported by Y. Itoh (Tokyo) et al. for the high-Tc Cu-monolayer superconductor HgBa2CuO4+d (Hg-1201) over a wide doping range [Tc = 50 K, 72 K, 82 K (underdoping), 96 K (optimal doping), and 30 K (overdoping)], using the Cu NMR spin- echo technique. The authors found that (1) both the static and dynamic spin susceptibilities exhibit pseudo spin-gap behavior over a wide q region around the staggered mode Q, (2) the dynamical pseudo spin gap in 1/T_1T can be ascribed mainly to the static one in 1/T_G, and (3) the spin-fluctuation amplitude probed by the ratio T_1T/(T_G)^2 is a monotonically decreasing function of the doping level but is not proportional to Tc. The authors find support for a superconductivity mechanism involving antiferromagnetic spin fluctuations, in which high- frequency spin fluctuations promote pairing but low-frequency spin fluctuations have a depairing effect. The authors suggest that a pseudo spin gap of an appropriate size works as one of the essentials for high Tc, in that such a gap suppresses the low-frequency spin-fluctuations and their associated depairing effect.

Unpolarized inelastic neutron scattering has been used by P. Dai (Oak Ridge) et al. to study the temperature and wavevector dependence of the dynamical magnetic susceptibility chi"(q,omega) of a well-characterized single crystal of underdoped YBa2Cu3O6.6 (Tc = 62.7 K). The authors find that a pseudogap opens in the spin-fluctuation spectrum at temperatures well above Tc. The authors speculate that the appearance of low-frequency incommensurate fluctuations is associated with the opening of the pseudogap. To within the error of the measurements, a gap in the spin fluctuation spectrum also is found in the superconducting state.

In a related paper, H. A. Mook (Oak Ridge) et al. report neutron scattering measurements of the spin fluctuations in YBa2Cu3O7-d for different oxygen doping levels. Incommensurability is clearly observed for oxygen concentrations of 6.6 and 6.7, and is suggested for 6.93. Measurements of the 34 meV resonance peak for O6.6 (Tc = 62.7 K) show that it exists, though in a broadened and less intense form, at temperatures as high as 150 K.

RBa2Cu3O7-d

The ab-plane optical conductivity sigma_[ab] for both twinned and untwinned YBa2Cu3O7-d as a function of temperature and doping has been analyzed by D. Mihailovic (Ljubljana) et al. The authors conclude that below a well-defined temperature T*, a dip in the spectrum systematically appears, separating the infrared charge excitation spectrum into two components with distinct energy scales. The change from monotonic behavior in sigma_[ab] is found to be concurrent with the onset of phonon anomalies in Raman and infrared spectra below T*. The authors suggest that the optical data are evidence for the appearance of an inhomogeneous distribution of carriers, rather than the opening of a simple gap for charge excitations below T*, an interpretation that is consistent with recent angle-resolved photoemission and electronic Raman spectra. The authors find that the behavior below T* and the absence of any anomalies at Tc can be interpreted in terms of a Bose-Einstein condensation of preformed pairs.

According to a preprint by P. Odier (Orleans) et al., the YBa2Cu3O7-d phase accommodates Cu deficiency up to several percent. Copper vacancies are located in the CuO chains at the Cu(1) site.

A TEM study of the degree of grain-boundary misorientation in melt- textured YBCO fabricated by the liquid-phase-removal method (LPRM) is reported in a preprint by M. K. Mironova et al. (TCSUH).

A preprint by M. S. Wong (TCSUH) et al. reports studies of a melt- textured YBa2Cu3O7-d composite containing MgO whiskers. While the cleavage-fracture resistance was improved by the MgO-whisker addition, the superconducting properties were reduced, possibly due to interdiffusion of Mg, Ba, and Cu.

Melt-textured composites of SmBa2Cu3O7-d/Sm2BaCuO5 (Sm-123/Sm-211) and NdBa2Cu3O7-d/Nd4Ba2Cu2O10 (Nd-123/Nd-422) have been prepared and studied by A. W. Kaiser et al. (Karlsruhe). The Sm-123/Sm-211 composites show good results of microstructure, as evidenced by flux maps, as well as high Jc and high levitation forces. Fabrication of Nd-123/Nd-422 composites is more complicated and is not yet optimized. The critical current density of both Sm-123 and Nd-123 was found to be superior to that of Y-123, even in high magnetic fields.

The transport critical current density of filamentary Nd-123 superconductors produced by solution spinning and an oxygen-controlled melt-growth process has been measured by M. Takahama (Nagoya) et al. The authors found that the filamentary Nd-123 superconductor exhibited Jc values higher than those in filamentary Y-123 in high magnetic fields. By controlling the melt-growth process and post-annealing conditions of a filamentary Nd1.18Ba2.12Cu3.09O7-d superconductor prepared in flowing 1% O2 + Ar, the authors achieved 77 K Jc values exceeding 10^4 A/cm^2 in self-field and 10^3 A/cm^2 in 10 T.

Bi Cuprates

An anomalous suppression of superconductivity (Tc suppression) at p (the hole concentration per Cu) ~ 1/8 in partially Zn-substituted Bi2Sr2Ca1- xYx(Cu1-yZny)2O8+d with x = 0.30 - 0.35 and y = 0.02 - 0.03 has been found by M. Akoshima et al. (Tohoku). In these samples, transport properties such as electrical resistivity and thermopower also exhibit less metallic behavior at p ~ 1/8. The authors suggest that some kind of ordering of holes and/or spins, stabilized via pinning by Zn, is responsible, and they propose that the so-called 1/8 problem found in La2-xBaxCuO4 and La2-x-yRySrxCuO4 is also common to all high-Tc materials with CuO2 planes in their crystal structures.

The effects of Ag substitution for Bi, Sr, and Cu on the c-axis lattice parameter and the critical temperature Tc have been determined by T. A. Deis (Pittsburgh) et al. for the Bi2-xSr2-yCaCu2-zO8+d (Bi-2212) superconducting phase. The authors observed two regimes of behavior: fast cooling, for which the uptake of excess oxygen was the controlling factor for the structure and properties, and slow cooling, for which the cation content was the controlling factor.

Bi2Sr2CaCu2O8+d (Bi-2212) tapes have been fabricated by R. L. Meng et al. (TCSUH) on inexpensive Ni substrates with a shorter annealing time using a simple two-step spray/press process. The 4.2 K critical current density of the tapes was found to be 5 x 10^5 A/cm^2 at 0 T; and 3 x 10^5 A/cm^2 and 1.5 x 10^5 A/cm^2 in 8 T fields parallel and perpendicular to the current, respectively. The authors note that these results compare favorably with the best previous results reported for Bi-2212 tapes in a Ag sheath or on a Ag substrate.

As reported by M. S. Wong and S. S. Wang (TCSUH), the introduction of Bi-2212 whiskers into (Bi,Pb)-2223 formed from a Bi1.70Pb0.34Sr2.03Ca1.90Cu3.06O10+d precursor does not improve flux pinning and Jc of the resulting composite.

The partitioning of lead between phases in the nominal five-phase assemblage of (Pb,Bi)3Sr2Ca2CuOx + (Ca,Sr)2PbO4 + (Bi,Pb)2Sr2CaCu2Ox + (Ca,Sr)O + liquid at 830^oC in an atmosphere of 7.5 volume % O2 and 92.5 volume % Ar has been investigated by L. P. Cook and W. Wong-Ng (NIST- Gaithersburg). The authors find an apparent saturation of Pb in the (Bi,Pb)2Sr2CaCu2Ox superconducting phase at a relatively low level.

As reported in a preprint by S. E. Dorris (Argonne) et al., the motivation for coated-wire-in-tube (CWIT) processing of Bi-2223/Ag superconductors is that most of the supercurrent is carried in a thin layer near the silver/superconductor interface. In CWIT processing, fine silver wires (diameter 75-125 micrometers) are coated with Bi-2223 (Bi2Sr2Ca2Cu3O10+d) precursor powder (coating thickness 25-100 micrometers), loaded into a silver tube, and then processed as in conventional powder-in-tube processing. This increases the silver- superconductor interface area by factors of ~~10 relative to monofilaments and ~~3 relative to multifilaments. Because the silver is added as wires, not as particles or whiskers, it provides a continuous substrate on which Bi-2223 grains can align themselves. As a result, Jc increases monotonically with the silver/superconductor interface area per unit superconductor area when the well-aligned regions remain continuous along the length of the conductor. The results are consistent with evidence that the superconducting properties of material at the silver/superconductor interface are superior to those of material in the core interior, and demonstrate that increasing the silver/superconductor interface area may enhance tape performance.

The importance of Pb in the formation of the high-Tc superconducting 2223 phase in (Bi,Pb)-2223/Ag tapes has been studied by A. Trautner et al. (Tuebingen). The authors found that the main effects of Pb in the phase-forming process are: (i) acceleration of the 2223 formation via rapid generation of (Bi,Pb)-2212, (ii) introduction of grain growth and texture, (iii) increase of the temperature window for 2223 formation, (iv) decrease of the reaction temperature, (v) adjustment of the hole concentration of the 2223 phase, (vi) operation as buffer for charge carriers via the temperature-dependent equilibrium between Pb^[4+] and Pb^[2+], and (vii) creation of Pb-containing pinning centers.

Using hard x-ray diffraction with a photon energy of 100 keV, H. F. Poulsen (Riso) et al. have simultaneously determined the phase composition and texture of the (Bi,Pb)-2223 core in Ag-clad tapes without any removal or modification of the silver cladding. The authors made room-temperature measurements on tapes at various stages of the thermomechanical processing, and did an in-situ study during annealing of the as-rolled tapes, to learn that the alignment of the superconducting grains takes place almost exclusively in the Bi-2212 phase. During the initial heating, the texture profile narrows rapidly above 750^oC, coincident with the dissolution of (Ca,Sr)2PbO4. A 98% conversion of Bi-2212 to Bi-2223 is obtained within 19 hours, but furnace cooling leads to the formation of secondary phases such as Bi- 2201 and (Ca,Sr)2PbO4.

Other Cuprates

The effect of Ce substitution on the magnetic excitations of Nd in Nd2- xCexCuO4 have been studied by W. Henggeler (ETH-Zurich and PSI) et al. via inelastic neutron scattering. The authors observe a strong softening of the spin waves upon doping, arising from a decrease of the Cu-Nd exchange field at the Nd site. A high spin-wave density of states is thereby created at low energies, leading to giant values of gamma = C/T at low temperatures. As the authors stress, this demonstrates that the magnetism of the Nd ions is the only source of the large gamma values found in specific-heat experiments, and that Nd2-xCexCuO4 thus must be excluded as a prototype of a novel heavy-fermion system.

For small x, La2-xSrxCuO4 is an antiferromagnetic insulator, with the Neel temperature T_N decreasing to zero when x reaches the critical Sr concentration, x_c = 0.02. A preprint by P. Caretta (Pavia) et al. reports results of [63]^Cu NQR spin-lattice relaxation measurements in the doping range just below and just above x_c, providing some evidence for the presence of dynamical charge separation in domain walls or stripes.

The effect of pressure on the superconducting transition temperature Tc of (Hg,Au)Ba2Ca2Cu3O8+d [(Hg,Au)-1223] has been measured by C. Acha et al. (Grenoble). Even for a high degree of overdoping, Tc increases with applied pressure, suggesting that it is not just the change of charge transfer between the reservoir blocks and the CuO2 planes that enhances Tc. Instead, the authors show that the change in the proximity effect induced by the decrease of the distance between copper-oxide blocks can account for the increase of Tc below 10 GPa.

Details of the formation of the superconductor Sr3Cu2O5Cl (Tc = 70 K), which previously was identified using scanning SQUID petrology, have been studied by D. Walker (Lamont-Doherty Earth Observatory, Columbia) et al. The authors report high-pressure and -temperature preparation conditions that yield phase assemblages with high Meissner fraction.

A preprint by B. R. Hickey et al. (TCSUH) reports the synthesis of a new superconducting compound (Ba,Sr)2CaCu2O6+x with Tc ~ 106 K. The cation composition was Ba:Sr:Ca:Cu ~~ 1.49:0.93:2.24:3.5.

A preprint by T. Noji et al. (Tohoku) reports the growth of single crystals of the layered cuprate Sr14-xCaxCu24O41, which consists of two- dimensional Cu2O3 ladder planes (spin-1/2 ladders with two legs) and one-dimensional CuO2 chains. The authors used NaCl as a flux to grow crystals of dimensions 1 x 0.05 x 1.5 mm^3 (x = 0) and 0.3 x 0.05 x 2 mm^3(x = 6.8). The authors also report anisotropic properties of the electrical resistivity and the thermoelectric power of these single crystals.

Vortices

A paper by A. Houghton and I. Vekhter (Brown) derives generalized quasiclassical transport equations that include the terms responsible for the Hall effect in the vortex state of a clean type-II superconductor, and they calculate the conductivity tensor for an s-wave superconductor in the high-field regime. The authors find that below the superconducting transition, the contribution to the transverse conductivity due to dynamical fluctuations of the order parameter is compensated by the modification of the quasiparticle contribution. In this regime, the nonlinear behavior of the Hall angle is governed by the change in the effective quasiparticle scattering rate due to the reduction in the density of states at the Fermi level.

As emphasized by F. Gollnik and R. P. Huebener (Tuebingen), the interpretation of experimental data on the Nernst and Seebeck effect in the mixed state of a type-II superconductor requires a careful treatment of the temperature-dependent electrothermal conductivity S_n(T)/rho_n(T) below Tc (S_n = Seebeck coefficient, rho_n = resistivity). For the cuprate superconductors such as YBa2Cu3O7-d, a simple extrapolation from the normal-state behavior above Tc is inadequate and can lead to erroneous results due to the opening of the superconducting energy gap and its effect on the temperature dependence of the quasiparticle scattering rate. In particular, the value of the thermal Hall angle of vortex motion depends sensitively upon the correct treatment of the electrothermal conductivity below Tc. Taking experimental data for YBa2Cu3O7-d films as an example, the authors show that the thermal Hall angle of vortex motion obtained from the data attains the expected small value only if the opening of the energy gap below Tc is taken into account.

A preprint by S. A. Grigera et al. (Bariloche) reports experiments in heavily twinned YBa2Cu3O7-d single crystals demonstrating that when the vortex correlation length in the liquid state becomes of the order of the sample thickness, size effects dominate the transport properties of the macroscopic vortex structures, implying a nonlocal response in flux- transformer experiments.

Measurements of the c-axis magnetoresistance and I-V characteristics in magnetic fields along the c axis in heavy-ion-irradiated single crystals of Bi-2212 are reported by N. Morozov et al. (Los Alamos). The results display distinct anomalies near fractional filling of the columnar defects created by the irradiation. The anomalous behavior extends over a limited range of temperature and in many crystals is manifested by a minimum in rho_c(H). The region of temperature and field where these anomalies appear coincides with that where double Josephson-plasma- resonance lines recently have been observed. The authors stress that the measurements directly show that a reduced pancake and phase-slip mobility is associated with columnar defect filling in the vortex-liquid state.

As noted by L. N. Bulaevskii (Los Alamos) et al., resistivity, reversible-magnetization, and Josephson-plasma-resonance data for Bi- 2212 with columnar defects show that two liquid phases exist above the irreversibility line. The two phases differ in the degree of c-axis correlation in pancake positions. The authors explain the existence of the two liquids and the transition between them by exploring the particle-hole symmetry in the free-energy functional for pancakes inside columnar defects.

Using the London approximation within the high-field scaling regime, M.J.W. Dodgson (ETH-Zurich) et al. have calculated the jump in the specific heat Delta[c] at the first-order-melting transition of the vortex lattice in YBa2Cu3O7-d. The authors demonstrate how a correct treatment of the temperature dependence of the model parameters, which are singular at the mean-field B_[c2] line, leads to good agreement between the predictions of the London model and the size of the experimental jump. Using continuum anisotropic scaling theory, the authors demonstrate the consistency of measurements at different angles of the magnetic field with respect to the crystal c axis.

Simulations of vortex-lattice melting have been carried out by A. K. Nguyen and A. Sudbo (Trondheim) using the uniformly frustrated anisotropic three-dimensional XY model. At the melting transition, the authors obtain an entropy jump of Delta[S] = 0.1 k_B per pancake vortex, which is smaller than the experimental value of Delta[S[ ~~ 0.4 k_B found experimentally in YBCO. The authors attribute the difference to the lower mass anisotropy (M_z/M)^[1/2] = 3 used in their simulations.

The time dependence of turbulent flux patterns in an untwinned YBa2Cu3O7-d single crystal showing a meandering instability at 65 K has been observed by M. R. Koblischka (Oslo) et al. using magneto-optical imaging. When a reversed external field is applied to a sample in the remanent state, flux droplets form along the front of penetrating antivortices. The flux droplets can separate from the flux front and move in a spiral-like fashion.

Exploiting a model based on the critical state for bulk specimens, M.A.R. LeBlanc (Ottawa) et al. have developed an explanation for the different rates of decay of remanent magnetic moments in granular high- Tc superconductors where the temperature-field histories generate trapped-flux profiles comprising two concentric regions of counter- circulating persistent currents.

The low-frequency out-of-plane (perpendicular to the superconducting layers) impedance (resistivity rho_c and the imaginary part rho_c^[lm]) versus temperature at various fields has been measured by C. Pham-Phu (Orsay) et al. in a sample of kappa-(BEDT-TTF)2Cu(N(CN)2)Br (Tc = 11.6 K). When the sample was cooled in field, the authors obtained a magnetic field vs. temperature phase diagram with a structure similar to that observed in other layered superconductors. However, when the magnetic field was applied at very low temperatures (2.7 K) after zero- field cooling, the authors found that the resistivity remained zero even up to 50 kOe, even though the melting line obtained from data taken after field cooling indicated that melting should occur at 30 kOe. Based on such magnetic-history-dependent effects, the authors claim that after zero-field cooling a new solid phase appears, which the authors call a Wigner solid. The authors also find that the zero-field-cooled field-versus-temperature phase diagram differs significantly from that obtained after field cooling.

A preprint by V. B. Geshkenbein (ETH-Zurich and Landau Institute) et al. shows that recent measurements of the magnetic-field dependence of the magnetization, specific heat, and resistivity of overdoped (Tc ~ 17 K) Tl2Ba2CuO6+d (Tl-2201) in the vicinity of the upper critical field H_[c2] imply that the vortex viscous drag coefficient is anomalously small and that the material studied is inhomogeneous with small (a few hundred Angstroms) regions in which the local Tc is much higher than the bulk Tc. The anomalously small viscous drag coefficient can be derived from a microscopic model in which the quasiparticle lifetime varies dramatically around the Fermi surface, being small everywhere except along the zone diagonal (cold spots). The authors propose experimental tests of their model.

Theory

A Boltzmann-equation analysis of the transport properties of a model of electrons with a lifetime that is short everywhere except near the Brillouin zone diagonals (cold spots) has been carried out by L. B. Ioffe (Rutgers) and A. J. Millis (Johns Hopkins). The anomalous lifetime is directly implied by photoemission and c-axis transport in high-Tc cuprates. The authors find quantitative agreement between calculations and ac and dc longitudinal and Hall resistivity, but the predicted longitudinal magnetoresistance disagrees with experiment. A possible microscopic origin of the anomalous lifetime is discussed.

The Knight shift and the 1/T_1 and 1/T_2 rates of YBa2Cu3O6+x in the normal and superconducting states have been modeled by F. Mack (Stuttgart) et al. by calculating the magnetic susceptibility in the bilayer Hubbard model within various approximations. Using the RPA approximation, the authors found an optimal set of parameters that fits the experiments in YBCO for optimal and nearly optimal doping. The authors find that the numerical analysis in the superconducting state strongly supports the idea of d-wave pairing in YBCO with much stronger intraplane pairing than interplane pairing.

As noted in a preprint by E. H. Kim (UC-Santa Barbara), the conductivity sum rule for a one-band hopping model relates the integrated spectral weight of the real part of the conductivity to the average kinetic energy. The author considers the consequences of this for the c-axis penetration depth of a layered system in which the charge transfer perpendicular to the layers (along the c axis) is mediated by interlayer impurity scattering.

Self-consistent calculations of the electronic structure near strongly scattering impurities in cuprate superconductors described by a realistic band structure and order-parameter magnitude are presented by M. E. Flatte (Iowa) and J. M. Byers (NRL). The authors determine energies and highly asymmetric lineshapes of resonances, changes in gap- edge features, local changes in the order parameter, and the local density of states [as measured by scanning tunneling microscopy (STM)] for magnetic and nonmagnetic potentials. The authors report that experimental tunneling spectra are well fit by calculations using a d- wave order parameter.

The application of the coherent potential approximation (CPA) to a simple model for disordered superconductors with d-wave pairing is described in a preprint by G. Litak (Lublin) et al. The authors demonstrate that while the effectiveness of an electronic Van Hove singularity to enhance Tc is reduced by disorder, it is not eliminated. The authors give a qualitative account of changes in the Tc vs. doping curve with increasing disorder and compare their results with experiments on Y0.8Ca0.2Ba2(Cu1-xZnc)3O7-d alloys.

The effect of nonmagnetic and magnetic defects and impurities on the Tc of superconductors with different gap anisotropy has been studied theoretically by L. A. Openov (Moscow State Engineering Physics Institute) in the BCS weak-coupling limit. The author discusses d-wave, (s+d)-wave, and anisotropic s-wave superconductors.

A preprint by A. T. Alastalo (Helsinki University of Technology) et al. introduces a new Phi-derivable approach for the Anderson impurity model in a BCS superconductor. The regime of validity of this conserving theory extends well beyond that of the Hartree-Fock approximation. The authors note that this is the first generalization of the U-perturbation theory to encompass a superconductor.

A nonmonotonic magnetic-field dependence for the electronic thermal conductivity kappa of clean superconductors with nodes of the order parameter on the Fermi surface is predicted in a preprint by Yu. S. Barash (Lebedev Institute and Grenoble) and A. A. Svidzinsky (Lebedev Institute and Stanford). At low fields and low temperatures, the authors find approximate scaling of the thermal conductivity with a single parameter x = (T/Tc)(B_[c2]/B)^[1/2]. The author's results are in qualitative agreement with recent experimental data for UPt3.

As shown by R. A. Riedel and P. F. Bagwell (Purdue), the height and width of the low-temperature peak in the critical current of Josephson junctions containing d-wave order parameters, found recently by Yu. S. Barash et al., Phys. Rev. Lett. 77, 4070 (1996), is limited by the transmission coefficient T through the insulator separating the two superconductors. The width of the Josephson-current peak in temperature is found to be TcT^[1/2], and its height is I_cR_n = pi[Delta]/eT^[1/2]. The height and width of the low-temperature Josephson-current peak follow from the bound Andreev-level spectrum in the junctions.

Thin Films

Planar tunneling in junctions of YBCO/I/Cu junctions, in which an organic monolayer is used to form the insulator, is discussed in a preprint by L. H. Greene et al. (Illinois-Urbana). The reproducible dependencies of the tunneling conductance on temperature, magnetic field, and ion-induced disorder show that the zero-bias conductance peak (ZBCP) is a surface-induced Andreev bound state of the d-wave order parameter.

As noted by C. Prouteau (ORNL and Illinois-Chicago) et al., the critical current density of high-Tc superconducting thin films has been found to be sensitive to the presence of flux-pinning defects, particularly grain boundaries, which may act either as pinning centers for the vortices or as weak-link junctions. The authors show that atomic-resolution Z- contrast imaging and spatially resolved electron-energy-loss spectroscopy provide methods to obtain direct images of the atomic grain-boundary structure for correlation with its electronic structure. Using a combination of transport measurements and electron microscopy, the authors have begun to correlate superconducting properties with atomic-scale grain-boundary structure using YBCO thin films deposited on SrTiO3 bicrystals and on Ni substrates (RABiTS). A closely related paper by N. D. Browning (Illinois-Chicago) explains the exponential decrease in Jc as a function of the grain-boundary angle in terms of dislocations at the grain boundary; the resulting strain fields perturb the local electronic structure and lead to nonsuperconducting zones at the grain boundary.

The oxidation state of a metal surface (such as Ni) during the initial stages of deposition of an epitaxial oxide buffer layer has been analyzed by T. J. Jackson et al. (Cambridge) using a thermodynamic viewpoint. The authors stress that the basic problem is one of minimizing oxidation of the metal's surface while ensuring that the buffer-layer oxide is able to form in the desired phase. Particular attention is paid to the deposition onto Ni of CeO2, SrTiO3, and Y2O3- ZrO2 (YSZ), which are candidates for use in the production of second- generation high-Tc coated conductors. Calculation of the Gibbs free energy changes for the oxidation reactions under various regimes of vacuum and gas supply suggest conditions that are reducing for the metal oxide but for which the buffer-layer oxide remains stable.

The growth of YbBa2Cu3O7-d (Yb-123) films by pulsed laser deposition is reported by M. S. Ramachandra Rao (IIT-Madras) et al. The best Tc and 77 K Jc values obtained were 88 K and 2.6 x 10^6 A/cm^2.

Planar-magnetron-sputtered ErNi2B2C films have been characterized by A. Andreone (Napoli) et al. using a variety of methods (dc resistivity, critical current, magnetization, critical fields, STM, and microwave measurements of the penetration depth). The results are in qualitative agreement with existing theories of antiferromagnetic superconductors.

Applications

To assist in the development of superconducting thin films or multilayer structures suitable for superconducting flux-flow transistors (SFFTs), P. Bernstein (Cherbourg) et al. have proposed a model to describe the current-voltage characteristics measured on microbridges in the flux- creep regime. The authors show how the effective superconducting thickness of the samples, as well as the pinning potential range, maximum vortex velocity, pinning energy, and depinning current of the vortices, can be determined. The model is applied to YBCO microbridges.

Different dc SQUIDs for galvanometer-type high-Tc SQUID sensors have been investigated by V. Schultze et al. (Jena). The aim was to achieve a high flux-to-voltage transfer function and high sensitivity to the current generated in a directly coupled pickup loop, and to investigate stability against external fields. The authors compared two- and three- junction YBCO SQUIDs with various layouts and found that the three- junction SQUID showed no advantage for application in a galvanometer- type SQUID sensor. Long SQUID loops with narrow lines gave the best results.

A theoretical analysis of Andreev-level spectroscopy and Josephson- current switching in a three-terminal Josephson junction is given in a preprint by H. T. Ilhan et al. (Purdue). The authors show that the voltage V applied to a normal-metal side probe controls the occupation of Andreev energy levels and therefore controls the Josephson current flowing through these levels.

Other Activities

The ac transport losses in high-temperature-superconducting wires and cables have been investigated by T. Fukunaga (Gifu) and A. Oota (Toyohashi) using numerical calculations based on Norris theory. The authors find that the losses in cables are generated mainly at the edges of the superconducting tapes. The authors suggest that decreasing the distance between adjacent tapes in the cylindrical cables should inhibit the edge effect and lower the ac transport losses of the cables.

The influence of an external field upon the current-voltage characteristics and the critical current density Jc of high-temperature superconductors has been studied by A. Kilic (Zonguldak) et al. The authors examined how the resistivity varies as a function of the angle theta between the field H and the current J.

As reported by V. Bekeris (Buenos Aires) et al., transport properties in patterned isotropic (granular) high-Tc superconducting samples have been investigated numerically and experimentally for boundary conditions imposing an inhomogeneous current flow. The results support a local description, where long-range correlations on the mm scale are absent.

The low-temperature properties of two ternary nickel carbides, one superconducting and the other magnetic, are reported by V. K. Pecharsky et al. (Ames Lab, Iowa State). The authors report that LaNiC2 is superconducting below Tc = 2.7 K, where the specific heat decreases exponentially with decreasing temperature (BCS-like behavior). CeNiC2 orders antiferromagnetically below 18 K. Both LaNiC2 (in its normal state) and CeNiC2 have the same heat capacity slope, gamma = 6.5(2) mJ/mol K^2, which is typical for many lanthanide-based intermetallic compounds.

The temperature dependence of magnetic ordering and the superconducting transition of polycrystalline HoxLu1-xNi2B2C compounds have been measured by J. Freudenberger et al. (Dresden) using susceptibility, resistivity, and neutron diffraction. The authors report a complete breakdown of de Gennes scaling of Tc for x > 0.7, where Tc becomes independent of the effective de Gennes factor.

Overviews

A book chapter on high-pressure measurements of the cuprates has been prepared by M. Nunez-Regueiro and C. Acha (Grenoble). The authors survey the experimental techniques, explain the approaches used in analyzing the data, and then present an overview of results on La2- xAxCuO4 (A = alkaline earth), YBa2Cu3O6+x, bismuth cuprates, thallium cuprates, copper-carbonate superconductors, and the mercury cuprates. The Tc of HgBa2Ca2Cu3O8+d (Hg-1223) rises to about 160 K under a pressure of 25 GPa (122 refs.).

The use of inelastic neutron scattering to study magnetic excitations in rare-earth-containing high-temperature superconductors has been summarized by W. Henggeler and A. Furrer (ETH-Zurich and PSI). The authors consider single-ion, cluster, and collective magnetic excitations, which are directly related to the fundamental interactions associated with the rare-earth sublattice. For HoxY1-xBa2Cu3O7, for example, the authors discuss crystalline-electric-field and cluster excitations, which provide information on the electrostatic potential and the magnetic pair coupling at the rare-earth site (38 refs.).

An overview of recent world-wide advances in the development of high-Tc superconductors for electric power applications has been prepared by U. Balachandran (Argonne). The author briefly describes progress in U.S. Department of Energy activities in wire development, systems technology development, and the Superconductivity Partnership Initiative; in SPI, there are four teams, which are developing superconducting fault-current limiters, generators, motors, and power cables. In addition, industry- led teams are working on superconducting transformers, flywheels, and transmission cables. The author also discusses efforts in Japan, Canada, and Europe regarding flywheels with superconducting bearings, transmission cables, transformers, fault-current limiters, and superconducting magnetic energy storage (SMES) (52 refs.).

Ph.D. Theses

The development of a magneto-optical set-up using a high-pressure mercury lamp, an interference filter, precision polarizers, and an eight-bit CCD camera, and the use of this apparatus to measure flux- density profiles in YBa2Cu3O7-d films and crystals are reported in the Ph.D. thesis of M. Baziljevich (Oslo). The author developed (a) a procedure to invert the measured flux-density distribution into a sheet- current distribution and (b) a method by which the temperature dependence of the critical current density Jc could be measured over the temperature range 25-80 K. The author also observed turbulent flux structures during remagnetization of detwinned YBCO crystals (178 refs.).

The Bariloche thesis of E. Morre presents an experimental study of the properties of the vortex-liquid phase in twinned single crystals of YBa2Cu3O7-d performed with the pseudo flux transformer. Under certain conditions, the author finds that the vortex liquid remains correlated in the entire angular range from H||c to H||ab. However, the Bose-glass solid-liquid phase transition is lost within small deviation angles theta of the magnetic field H from the c axis (128 refs.).

Contributed by John R. Clem

Contents: Technology News begins on page 8; Preprints begin on page 9; Coming Events begin on page 14; FYI is on page 15; and a figure mentioned in Technology News is on page 15.

High-Tc Update is available without charge to interested persons. Recipients are expected to participate in this information exchange by sending us preprints, reprints, meeting news, research news, etc. Contributions to defray the cost of newsletter printing and mailing are welcome.

TECHNOLOGY NEWS (Also see Applications section of Nota Bene.)

This section describes progress in manufacturing, product development, and technology transfer in the high-Tc superconductivity field. Please send your contributions (product development information, news regarding technology transfer efforts, or any information you would like to share about your corporation or laboratory) to the editor.

Electricite de France (EDF), American Superconductor Corporation (ASC), and ABB announced the signing of agreements for a $15 million, four- year, joint-development program the purpose of which is to accelerate the development of high-temperature superconducting (HTS) wire with important new functionality for power transformers. As part of the agreement, each partner will contribute $5 million to ASC for this program.

The annual market for conventional power transformers with power ratings more than 30 MVA, which are to be addressed by this new technology, is valued at approximately $3 billion worldwide. In a related agreement, ABB and EDF plan to manufacture a prototype 10 MVA transformer using the HTS wires manufactured by ASC. The 10 MVA transformer, which is a crucial next step on the path to commercial-scale 30 MVA transformers, is expected to be installed and tested at a substation within the power grid of EDF by the end of the year 2000. The 10 MVA prototype will handle 15 times more power than the first HTS transformer, which was demonstrated by ABB in cooperation with EDF and ASC, in Switzerland in March 1997.

The HTS transformers envisioned by this program will offer a number of improved features as well as entirely new functionality with important utility systems benefits relative to conventional transformers. Features and systems benefits are expected to include: (1) size and weight reduced by a factor of two, which will increase existing substation capacity, reduce land area needed for new substations, and greatly relieve transportation challenges currently faced by electric utilities for conventional power transformers; (2) replacement of the dielectric oil which surrounds the copper coils in today's power transformers with low-cost, environmentally-friendly liquid nitrogen, which will eliminate the fire and spill risks associated with oil dielectrics. This is expected to lower associated insurance costs and allow transformers to be installed closer to large load centers even within large cities; and (3) unprecedented fault current limiting functionality, which is expected to provide protection to and reduce the cost of utility system components. In addition, the new transformers are expected to have lower energy losses which will reduce total ownership costs, reduce emissions, and improve system efficiency. For further information, contact Kathryn Cadigan, American Superconductor Corporation, Two Technology Drive, Westborough, MA 01581; telephone (508) 836-4200; telefax (508) 836-4248. Other contacts: Stephan Albrechtskirchinger, Electricite de France in Paris, France; telephone +33 1 4042 3159; or John Fox, ABB in Zurich, Switzerland; telephone +41 1 317 7371.

Fabrication of a single entity HTS current lead system was announced by EURUS Technologies, Inc. as an innovative approach to supplying power to magnet systems. The design of the EURUS SX Series[TM] Bipolar Current Lead allows for the simultaneous processing of both supply and return and is configurable from 600 A to 100,000 A of current. Each bipolar lead contains all of the components to completely integrate the power lead into client-specific cryogenic requirements. A resistive section is included with each EURUS SX Series[TM] Bipolar Current Lead for efficient connection and uniform cooling to room temperature. The geometry of the lead minimizes the self field, which can often be substantial in high-current lead designs. Researchers at the Large Magnet System Group at the National High Magnetic Field Laboratory expect to install the EURUS current lead on their next generation hybrid magnet system for a considerable reduction in both capital and operating cryosystem budget. Building upon the success of the SL Series[TM] family of single pole HTS current leads, these new HTS power products expect to provide reliability, ruggedness, and extremely low heat leak. The HTS material is bulk, sintered YBCO which is encapsulated against environmental degradation. For further information, contact Sanford Cohen, Director of Sales and Marketing at EURUS Technologies, Inc., 2031 East Paul Dirac Drive, Innovation Park, Tallahassee, FL 32310; telephone (850) 574-1800; telefax (850) 574-2998; e-mail SCohen@TeamEURUS.com; Web site www.TeamEURUS.com. A figure of the SX Series[TM] Bipolar Current Lead in shown on page 15.)

Contributed by Sreeparna Mitra

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.

C. Acha, M. Nunez-Regueiro, S. Le Floch, P. Bordet, J. J. Capponi, C. Chaillout, and J.-L. Tholence, "Overdoped (Hg1-xAux)-1223 and the Origin of the Intrinsic Increase of Tc Under Pressure in Mercury Cuprates." To be published in Phys. Rev. B. Contact M. Nunez-Regueiro, EPM-Matformag and Centre National de la Recherche Scientifique, CNRS, BP 166, F-38042 Grenoble Cedex 9, FRANCE; e-mail nunez@labs.polycnrs-gre.fr. 74.62.Fj; 74.62.-c; 74.72.Gr; 74.25.Dw.

Megumi Akoshima, Takashi Noji, Yasuhiro Ono, and Yoji Koike, "Anomalous Suppression of Superconductivity in the Zn-Substituted Bi2Sr2Ca1- xYx(Cu1-yZny)2O8+d." To be published in Phys. Rev. B. Department of Applied Physics, Graduate School of Engineering, Tohoku University, Aramaki Aoba, Aoba-ku, Sendai 980-77, JAPAN; e-mail akoshima@teion.apph.tohoku.ac.jp. 74.25.Fy; 74.62.Dh; 74.72.Hs.

Ari T. Alastalo, Robert J. Joynt, and Martti M. Salomaa, "Anderson Model in a Superconductor: Phi-Derivable Theory." Materials Physics Laboratory, P.O. Box 2200, Helsinki University of Technology, FIN-02015 HUT, FINLAND; e-mail alastalo@focus.hut.fi; preprint also available at cond-mat@xxx.lanl.gov (#9712118). 72.15.Qm; 75.20.Hr; 75.30.Mb; 74.25.- q.

A. Andreone, C. Aruta, A. Cassinese, F. Fontana, M. Iavarone, F. Palomba, M. L. Russo, R. Vaglio, G. W. Crabtree, Y. De Wilde, and M. Polichetti, "Properties of ErNi2B2C Superconducting Thin Films." Submitted to Phys. Rev. B. Istituto Nazionale per la Fisica della Materia (INFM), Dipartimento di Scienze Fisiche, Universita di Napoli "Federico II," Piazzale Tecchio 80, I-80125 Napoli, ITALY; M. Iavarone's telephone +39 81 768-2420 or -2606; telefax +39 81 239-1821; e-mail iavarone@na.infn.it or iavarone@axpna1.na.infn.it.

U. Balachandran, "Recent Advances in the Development of High-Tc Superconductors for Electric Power Applications." Submitted to ISTEC Journal. Contact Janice Coble, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439; telefax (708) 252-9595; e-mail janice_coble@qmgate.anl.gov.

Yu. S. Barash and A. A. Svidzinsky, "Nonmonotonous Magnetic Field Dependence and Scaling of the Thermal Conductivity for Superconductors with Nodes of the Order Parameter." Submitted to Phys. Rev. B. P.N. Lebedev Physical Institute, Leninsky Prospect 53, Moscow 117924, RUSSIA; A. A. Svidzinsky's e-mail at Stanford University asvid@leland.stanford.edu; preprint also available at cond- mat@xxx.lanl.gov (#9801076). 74.25.Fy; 74.70.Tx.

Michael Baziljevich, "Investigation of Magnetic Flux Behavior in YBa2Cu3O7-d Thin Films and Single Crystals Using Magneto-Optic Imaging." Submitted as a Ph.D. thesis (University of Oslo). Department of Physics, University of Oslo, P.O. Box 1048, Blindern, 0316 Oslo, NORWAY.

V. Bekeris, R. Schifini Gladchtein, M. Monteverde, P. Dmitruk, H. Ferrari, G. Polla, and F. de la Cruz, "Non-Homogenous Transport Current Density and Voltage Distribution in Isotropic High Tc Superconductors." To be published in Physica C. Departamento de Fisica, Pabellon I, Ciudad Universitaria, 1428 Buenos Aires, ARGENTINA; telephone +54 1 782 1007; telefax +54 1 782 7647; e-mail lbtuba@df.uba.ar. Key words: transport properties, intergranular vortex phases. 74.25.Fy; 74.40.+k; 74.80.Bj.

P. Bernstein, C. Picard, M. Pannetier, Ph. Lecoeur, J. F. Hamet, T. D. Doan, J. P. Contour, and M. Drouet, "Characterization of the Vortex Dynamics in Abrikosov Superconductive Flux Flow Transistors." To be published in Appl. Supercond. LUSAC-EIC Site Universitaire de Cherbourg, F-50130 Octeville, FRANCE.

N. D. Browning, J. P. Buban, P. D. Nellist, D. P. Norton, M. F. Chisholm, and S. J. Pennycook, "The Atomic Origins of Reduced Critical Currents at [001] Tilt Grain Boundaries in YBa2Cu3O7-d Thin Films." To be published in Physica C (in press). Department of Physics (M/C 273), University of Illinois at Chicago, 845 W. Taylor Street, Chicago, IL 60607-7059; telephone (312) 413-8164; telefax (312) 996-9016; e-mail drhnb@uic.edu.

L. N. Bulaevskii, M. P. Maley, and V. M. Vinokur, "Vortex Phases in Irradiated Highly Anisotropic Layered Superconductors." Los Alamos National Laboratory, MS-K763, Los Alamos, NM 87545.

P. Carretta, F. Tedoldi, A. Rigamonti, F. Galli, F. Borsa, J. H. Cho, and D. C. Johnston, "Spin Dynamics in Hole-Doped Two-Dimensional S=1/2 Heisenberg Paramagnet: [63]^Cu NQR Relaxation in La2-xSrxCuO4 for x<=0.04." Submitted to Phys. Rev. B. Department of Physics "A. Volta," Unita' INFM and Sezione INFN de Pavia-Via Bassi 6, I-27100 Pavia, ITALY. 76.60.Es; 75.40.Gb.

Lawrence P. Cook and Winnie Wong-Ng, "Pb-Distribution in a Five-Phase (Bi,Pb)-Sr-Ca-Cu-O Assemblage." To be published in the Proc. of the Supercond. Symp. of the 1997 American Ceram. Soc. annual meeting, Cincinatti, Ohio, May 5-7, 1997. Contact Winnie Wong-Ng, A215 MATLS, National Institute of Standards and Technology, Gaithersburg, MD 20899; telephone (301) 975-5791; telefax (301) 975-5334; e-mail wongng@tiber.nist.gov.

Pengcheng Dai, H. A. Mook, and F. Dogan, "Pseudogap and Incommensurate Magnetic Fluctuations in YBa2Cu3O6.6." Oak Ridge National Laboratory, Oak Ridge, TN 37831-6393; e-mail piq@ornl.gov. Key words: high-Tc superconductivity, magnetic excitations.

T. A. Deis, M. Lelovic, N. G. Eror, and U. Balachandran, "Effect of Ag Doping on Structure and Critical Temperature of Bi2Sr2CaCu2O8+d Superconductors." Submitted to Appl. Supercond. Contact N. G. Eror, Department of Materials Science and Engineering, University of Pittsburgh, Pittsburgh, PA 15261; preprint also available from Janice Coble, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439; telefax (708) 252-9595; e-mail janice_coble@qmgate.anl.gov.

Matthew J.W. Dodgson, Vadim B. Geshkenbein, Henrik Nordborg, and Gianni Blatter, "Thermodynamics of the First-Order Vortex Lattice Melting Transition in YBa2Cu3O7-d." Institut fuer Theoretische Physik, ETH- Hoenggerberg, CH-8093 Zurich, SWITZERLAND; telephone +41 1 633-2573 or -2570; telefax +41 1 633 1115; e-mail mattd@itp.phys.ethz.ch; preprint also available at cond-mat@xxx.lanl.gov (#9712145). 74.60.Ec; 74.60.Ge.

S. E. Dorris, N. Ashcom, T. Truchan, N. Vasanthamohan, D. A. Burlone, and L. D. Woolf, "Coated-Wire-in-Tube Processing of Silver/Bismuth-2223 Superconductors." Presented at the 8th U.S.-Japan Workshop on High Temp. Supercond., Tallahassee, Fla., Dec. 8-10, 1997. Contact Janice Coble, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439; telefax (708) 252-9595; e-mail janice_coble@qmgate.anl.gov.

Michael E. Flatte and Jeff M. Byers, "Impurity Effects on Quasiparticle c-Axis Planar Tunneling and STM Spectra in High-Tc Cuprates." Submitted to Phys. Rev. Lett. Department of Physics and Astronomy, 203 Van Allen Hall, University of Iowa, Iowa City, IA 52242-1479; telephone (319) 335- 1686; telefax (319) 335-1753.

J. Freudenberger, G. Fuchs, K. Nenkov, A. Handstein, M. Wolf, A. Kreyssig, K.-H. Mueller, M. Loewenhaupt, and L. Schultz, "Breakdown of de Gennes Scaling in HoxLu1-xNi2B2C." Submitted to J. Magn. & Magn. Mater. Institut fuer Feskoerper- und Werkstofforschung Dresden, Postfach 270016, D-01171 Dresden, GERMANY; telephone +49 351 4659 553; telefax +49 351 4659 537; e-mail j.freudenberger@ifw-dresden.de. Key words: borocarbides, superconductivity, antiferromagnetism, de Gennes scaling. 74.70.-b; 74.70.Ad.

T. Fukunaga and A. Oota, "Numerical Analysis on ac Transport Losses of High Temperature Superconducting Wires and Cables." Presented at the Int. Cryogenic Eng. Conf. and the Int. Cryogenic Mater. Conf. (Joint CEC/ICMC 1997 Conf.), Portland, Oreg., July 27-Aug. 1, 1997. Department of Electronic and Control Engineering, Gifu National College of Technology, Shinsei-cho, Motosu-gun, Gifu 501-04, JAPAN; telephone +81 58 320 1383; telefax +81 58 320 1263; e-mail fukunaga@gifu-nct.ac.jp.

V. B. Geshkenbein, L. B. Ioffe, and A. J. Millis, "Theory of the Resistive Transition in Overdoped Tl2Ba2CuO6+d: Implications for the Angular Dependence of the Quasiparticle Scattering Rate in High-Tc Superconductors." Theoretische Physik, ETH-Hoenggerberg, CH-8093 Zurich, SWITZERLAND; L. B. Ioffe's e-mail at Rutgers University ioffe@pion.rutgers.edu; preprint also available at cond-mat@xxx.lanl.gov (#9801059).

F. Gollnik and R. P. Huebener, "Quasiparticle Transport Below Tc in the Cuprate Superconductors." To be published in Phys. Rev. B. Physikalisches Institut, Lehrstuhl Experimentalphysik II, Universitaet Tuebingen, Morgenstelle 14, D-72076 Tuebingen, GERMANY. 74.25.Fy; 74.76.Bz; 74.60.Ge.

L. H. Greene, M. Covington, M. Aprili, and E. Paraoanu, "Tunneling into Andreev Bound States of YBa2Cu3O7: Observation of Broken Time-Reversal Symmetry." To be published in J. Phys. Chem. Solids: Proc. of the Conf. on Spectroscopies in Novel Supercond. (SNS'97), Cape Cod, Mass., Sept. 14-18, 1997. Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801.

S. A. Grigera, E. Morre, E. Osquiguil, G. Nieva, and F. de la Cruz, "Nonlocal Transport Properties and Size Effects in Heavily Twinned YBa2Cu3O7-d Single Crystals." Submitted to Phys. Rev. B. Centro Atomico Bariloche and Instituto Balseiro, Comision Nacional de Energia Atomica, 8400 San Carlos de Bariloche, ARGENTINA; preprint also available at Web site http://cabbat1.cnea.edu.ar/~grigera/.

Z. H. He, Z. G. Ma, F. Q. Zhong, Y. Y. Luo, Q. Y. Li, M. Wu, and W. Gavalek, "Investigation of the Off-Diagonal Thermoelectric Effect on Textured YBa2Cu3O7-d." To be published in J. Supercond. Department of Physics, Zhongshan University, Guangzhou 510275, PEOPLE'S REPUBLIC OF CHINA; e-mail stshzh@zsu.edu.cn. Key words: thermoelectricity, high-Tc texture superconductor, anisotropy, oxygen content.

W. Henggeler, B. Roessli, A. Furrer, P. Vorderwisch, and Tapan Chatterji, "Correlations of the Nd Magnetic Moments and their Influence on the Specific Heat in Nd2-xCexCuO4." To be published in Phys. Rev. Lett. Laboratory for Neutron Scattering, Eidgenoessische Technische Hochschule Zurich & Paul Scherrer Institute, CH-5232 Villigen PSI, SWITZERLAND; telephone +41 56 310 20 89; telefax +41 56 310 29 39; e- mail henggeler@psi.ch. 74.72.Jt; 75.30.Ds.

Wolfgang Henggeler and Albert Furrer, "Magnetic Excitations in Rare- Earth Based High-Temperature Superconductors." To be published in J. Phys. Cond. Matt. Laboratory for Neutron Scattering, Eidgenoessische Technische Hochschule Zurich & Paul Scherrer Institute, CH-5232 Villigen PSI, SWITZERLAND; telephone +41 56 310 20 89; telefax +41 56 310 29 39; e-mail henggeler@psi.ch.

B. R. Hickey, Z. L. Du, Y. Y. Xue, D. K. Ross, L. M. Dezaneti, Y. Y. Sun, N. L. Wu, and C. W. Chu, "Observation of (Ba,Sr)2CaCu2O6+d with Tc ~ 106 K." Preprint #98:008; submitted to Physica C. Texas Center for Superconductivity, University of Houston, Houston, TX 77204-5932; telephone (713) 743-8200; telefax (713) 743-8201; e-mail preprints@www.tcs.uh.edu. Key words: (Ba,Sr)2CaCu2O6+d , substitution. 74.72.Jt; 74.62.Bf; 61.66.Fn.

A. Houghton and I. Vekhter, "Quasiclassical Approach to Transport in the Vortex State and the Hall Effect." Department of Physics, Brown University, Providence, RI 02912-1843; I. Vekhter's e-mail at University of Guelph in Ontario, Canada vekhter@anik.physics.uoguelph.ca; preprint also available at cond-mat@xxx.lanl.gov (#9712272). 74.25.Fy; 74.60.-w; 74.60.Ge.

H. Tolga Ilhan, H. Volkan Demir, and Philip F. Bagwell, "Andreev Level Spectroscopy and Josephson Current Switching in a 3-Terminal Josephson Junction." Submitted to Phys. Rev. B. School of Electrical Engineering, Purdue University, West Lafayette, IN 47907; Philip F. Bagwell's e-mail bagwell@ecn.purdue.edu; preprint also available at cond-mat@xxx.lanl.gov (#9712284). 74.80.Fp; 74.50.+r; 73.20.Dx.

L. B. Ioffe and A. J. Millis, "'Cold Spots': A New Model for Transport in High Tc Cuprates." Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854; e-mail ioffe@pion.rutgers.edu; preprint also available at cond-mat@xxx.lanl.gov (#9801092).

Yutaka Itoh, Takato Machi, Seiji Adachi, Atsushi Fukuoka, Keiichi Tanabe, and Hiroshi Yasuoka, "Pseudo Spin-Gap Spectrum in the Monolayer HgBa2CuO4+d." Preprint #3312; to be published in J. Phys. Soc. Jpn. Institute for Solid State Physics, University of Tokyo, 7-22-1 Roppongi, Minato-Ku, Tokyo 106, JAPAN. Key words: NMR, high-Tc cuprate, monolayer, HgBa2CuO4+d, pseudo spin gap.

T. J. Jackson, B. A. Glowacki, and J. E. Evetts, "Oxidation Thermodynamics of Metal Substrates During the Deposition of Buffer Layer Oxides." To be published in Physica C. School of Physics and Space Research, University of Birmingham, Edgbaston, Birmingham B15 2TT, UNITED KINGDOM; telephone +44 121 414 7322; telefax +44 121 414 4719; e- mail jacksotj@novell5.bham.ac.uk. Key words: thin films, buffer layers, sputtering, pulsed laser ablation, thermodyamic properties, cerium oxide, superconductivity, metallic substrates, high-Tc coated conductors.

A. W. Kaiser, W. Hennig, and H. J. Bornemann, "Properties of Melt Textured Sm/Nd-Ba-Cu Composites." To be published in Physica C. Institut fuer Nukleare Festkoerperphysik, Forschungszentrum Karlsruhe GmbH, Postfach 3640, D-76021 Karlsruhe, GERMANY; telephone +49 7247 82 3981; telefax +49 7247 82 4624; e-mail axel.kaiser@infp.fzk.de; Web site http://www.infp.fzk.de. Key words: Nd-Ba-Cu-O, Sm-Ba-Cu-O, critical current density, remanent magnetization, levitation force.

A. Kilic, K. Kilic, S. Senoussi, and K. Demir, "Influence of an External Magnetic Field on the Current-Voltage Characteristics and Transport Critical Current Density." To be published in Physica C (in press). Department of Physics, Zonguldak Karaelmas University, 67100 Zonguldak, TURKEY; telefax +90 372 257 4181; e-mail kilica@elmas.bim.karaelmas.edu.tr. Key words: flux pinning, flux flow, critical current, magnetoresistivity. 74.25.Ha; 74.60.Ge; 74.60.Ec; 74.60.Jg.

Eugene H. Kim, "Penetration Depth and the Conductivity Sum Rule for a Model with Incoherent c-Axis Coupling." Department of Physics, University of California, Santa Barbara, CA 93106-9530; telephone (805) 893-8802; telefax (805) 893-2902; e-mail ehkim@physics.ucsb.edu; preprint also available at cond-mat@xxx.lanl.gov (#9712229).

M. R. Koblischka, T. H. Johansen, M. Baziljevich, H. Hauglin, H. Bratsberg, and B. Ya. Shapiro, "Turbulent Relaxation in the Vortex Lattice." Submitted to Europhys. Lett. Department of Physics, University of Oslo, Blindern, N-0316 Oslo, NORWAY; e-mail m.r.koblischka@fys.uio.no. 74.60.Ec; 74.60.Ge; 78.20.Ls.

M.A.R. LeBlanc, Daniel S.M. Cameron, Selahattin Celebi, and Jean- Philippe Pascal, "Effect of the Configuration of the Trapped Flux on the Decay Rate of Remanent Magnetic Moments in Type II Superconductors." To be published in Supercond. Sci. & Technol. Department of Physics, University of Ottawa, Ottawa, CANADA K1N 6N5; telefax (613) 562-5190; e- mail 76153.2047@compuserve.com. 74.60.Ge; 74.60.-w; 74.25.Ha; 74.72.-h.

G. Litak, A. M. Martin, B. L. Gyoerffy, J. F. Annett, and K. I. Wysokinski, "Van Hove Singularity and d-Wave Pairing in Disordered Superconductors." Department of Mechanics, Technical University of Lublin, PL-20618 Lublin, POLAND; A. M. Martin's e-mail at University of Bristol a.martin@bristol.ac.uk; preprint also available at cond- mat@xxx.lanl.gov (#9801035). 74.62.Dh; 74.20.-z.

Frank Mack, Miodrag L. Kulic, and Michael Mehring, "Theoretical Analysis of NMR Experiments in Normal and Superconducting States of High-Tc Superconductors." To be published in Physica C (in press). 2. Physikalisches Institut, Universitaet Stuttgart, Postfach 900665, D- 70563 Stuttgart, GERMANY; telephone +49 711 689 1506; telefax +49 711 689 1010; e-mail frank@audrey.mpi-stuttgart.mpg.de. 75.40.Cx; 75.40.Gb; 76.60.-k.

R. L. Meng, C. Garcia, Y. Q. Wang, W. N. Kang, I. A. Rusakova, and C. W. Chu, "Processing of Bi2Sr2CaCu2O8 Tapes at Low Cost." Preprint #98:001, submitted to Appl. Phys. Lett. Texas Center for Superconductivity, University of Houston, Houston, TX 77204-5932; telephone (713) 743-8200; telefax (713) 743-8201; e-mail preprints@www.tcs.uh.edu. Key words: high-temperature superconducting tapes, processing.

D. Mihailovic, T. Mertelj, and K. A. Mueller, "a-b Plane Optical Conductivity in YBa2Cu3O7-d Above and Below T*." To be published in Phys. Rev. B. Solid State Physics Department, Jozef Stefan Institute, Jamova 39, 1001 Ljubljana, SLOVANIA; +386 61 1773 729; telefax +386 61 1251 077; e-mail dragan.mihailovic@ijs.si; preprint also available at cond-mat@xxx.lanl.gov (#9801032).

M. K. Mironova, G. P. Du, S. Sathyamurthy, and K. Salama, "Determination of High-Angle Grain Boundary Misorientations in a Melt-Textured YBCO Using Transmission Electron Microscopy Studies of Intragrain Structure." Preprint #98:006; submitted to Philos. Mag. A. Texas Center for Superconductivity, University of Houston, Houston, TX 77204-5932; telephone (713) 743-8200; telefax (713) 743-8201; e-mail preprints@www.tcs.uh.edu.

H. A. Mook, P. Dai, R. D. Hunt, and F. Dogan, "Neutron Scattering Studies of the Magnetic Fluctuations in YBa2Cu3O7-d." Solid State Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6393; P. Dai's e-mail piq@ornl.gov; preprint also available at cond-mat@xxx.lanl.gov (#9712326). 74.72.Bk; 61.12.Ex.

N. Morozov, M. P. Maley, L. N. Bulaevskii, and J. Sarrao, "Reentrant c- Axis Magnetoresistance in Bi2Sr2CaCu2O8+d with Columnar Defects: Evidence for Recoupling of the Vortex Liquid." Submitted to Phys. Rev. Lett. Los Alamos National Laboratory, MS-K763, Los Alamos, NM 87545.

Eckhart H.J. Morre, "Variacion Angular de la Correlacion del Liquido de Vortices en YBa2Cu3O7-d Con Defectos Planares." Submitted as a Ph.D. thesis (Instituto Balseiro, San Carlos de Bariloche, Argentina). Laboratorio de Bajas Temperaturas, Centro Atomico Bariloche, 8400 San Carlos de Bariloche, ARGENTINA; e-mail eckhart@cab.cnea.edu.ar; Web site http://cabbat1.cnea.edu.ar. (Thesis in Spanish with English abstract.)

A. K. Nguyen and A. Sudbo, "On Phase-Coherence and the Boson-Analogy of Vortex Liquids." Department of Physics, Norwegian University of Science and Technology, N-7034 Trondheim, NORWAY; e-mail kietanh@phys.ntnu.no; preprint also available at cond-mat@xxx.lanl.gov (#9712264). 74.20.De; 74.25.Dw; 74.25.Ha; 74.60.Ec.

Takashi Noji, Katsumi Kakimoto, and Yoji Koike, "Growth by the Flux Method and Transport Properties of Sr14-xCaxCu24O41 Single Crystals." To be published in Jpn. J. Appl. Phys. Department of Applied Physics, Graduate School of Engineering, Tohoku University, Sendai 980-77, JAPAN; e-mail noji@teion.apph.tohoku.ac.jp. Key words: Sr14-xCaxCu24O41, spin-ladder system, crystal growth, flux method, electrical resistivity, thermoelectric power, anisotropy.

Manuel Nunez-Regueiro and Carlos Acha, "High Pressure Measurements on Mercury Cuprates." To be published in Studies of High Temp. Supercond., Vol. 24, edited by A. V. Narlikar (Nova Science Publishers Inc., New York). EPM-Matformag, CNRS, B.P. 166, Cedex 09, F-38042 Grenoble, FRANCE; e-mail nunez@labs.polycnrs-gre.fr.

Philippe Odier, Francisco J. Gotor, Nadia Pellerin, Ricardo P.S.M. Lobo, Kristof Dembinski, Jeannne Ayache, Henri Noel, Michel Potel, Jean Pierre Chaminade, and Gaston Collin, "Copper Deficiency in YBa2Cu3O7-x Ceramics: Textured and Single Crystals." To be published in Mater. Sci. & Eng. B. Centre de Recherches sur la Physique des Hautes Temperatures-CNRS, 1D Avenue de la Recherche Scientifique, F-45071 Orleans Cedex 2, FRANCE; telefax +33 238 638103; e-mail odier@cnrs- orleans.fr.

Leonid A. Openov, "Combined Effect of Nonmagnetic and Magnetic Scatterers on Critical Temperatures of Superconductors with Different Gap Anisotropy." Submitted to JETP Lett. Moscow State Engineering Physics Institute, Technical University, 115409 Moscow, RUSSIA; e-mail opn@supercon.mephi.ru; preprint also available at cond-mat@xxx.lanl.gov (#9711175). 74.20.-z; 74.62.Dh.

V. K. Pecharsky, L. L. Miller, and K. A. Gschneidner, Jr., "Low Temperature Behavior of Two Ternary Lanthanide Nickel Carbides: Superconducting LaNiC2 and Magnetic CeNiC2." 242 Spedding Hall, Ames Laboratory-USDOE, Iowa State University, Ames, IA 50011-3020; telephone (515) 294-8220; telefax (515) 294-9579; e-mail vitkp@ameslab.gov. 75.20.En; 74.70.Ad; 74.25.Bt; 74.25.Ha.

C. Pham-Phu, C. Pasquier, A. Deluzet, C. Plouvier, and P. Batail, "Wigner Solidification of Vortices in the Organic Superconductor kappa- (BEDT-TTF)2Cu[N(CN)2]Br." Submitted to Nature. Contact C. Pasquier, Laboratoire de Physique des Solides, Universite Paris-Sud, Batiment 510, F-91405 Orsay Cedex, FRANCE; telephone +33 1 69 15 5300; telefax +33 1 69 15 6086; e-mail pasquier@lps.u-psud.fr.

H. F. Poulsen, T. Frello, N. H. Andersen, M. D. Bentzon, and M. von Zimmermann, "Structural Studies of BSCCO/Ag Tapes by High-Energy Synchrotron X-ray Diffraction." To be published in Physica C. Materials Department, Riso National Laboratory, DK-4000 Roskilde, DENMARK; telephone +45 4677 5739; telefax +45 4677 5758; e-mail henning.friis.poulsen@risoe.dk. Key words: BSCCO/Ag tapes, superconductivity, synchrotron, texture, phase.

C. Prouteau, G. Duscher, D. K. Christen, N. D. Browning, S. J. Pennycook, M. F. Chisholm, D. P. Norton, A. Goyal, and C. Park, "Correlation of Transport Properties with Grain Boundary Atomic Structure in High Tc Superconducting Films and Tapes." Presented at the 10th Int. Symp. on Supercond. (ISS'97), Gifu, Japan, Oct. 27-30, 1997. Solid State Division, Building 3025, Mailstop 6031, Oak Ridge National Laboratory, Bethel Valley Rd., P.O. Box 2008, Oak Ridge, TN 37831; telephone (423) 241-3856; telefax (423) 574-4143; e-mail prouteau@solid.ssd.ornl.gov. Key words: YBCO, grain boundary, RABiTS, Z-contrast imaging, electron energy loss spectroscopy.

M. S. Ramachandra Rao, R. Pinto, S. Srinivas, and A. K. Bhatnagar, "Growth of High Quality YbBa2Cu3O7-d Thin Films by Pulsed Laser Deposition." To be published in Appl. Supercond. Materials Science Research Centre and Department of Physics, Indian Institute of Technology, Madras 600 036, INDIA.

Richard A. Riedel and Philip F. Bagwell, "Low-Temperature Josephsen Current Peak in Junctions with d-Wave Order Parameters." To be published in Phys. Rev. B. School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907; Philip F. Bagwell's e-mail bagwell@ecn.purdue.edu. 74.80.Fp; 74.50.+r; 74.80.Dm; 73.20.Dx; 74.20.Fg.

V. Schultze, R. Ijsselsteijn, V. Zakosarenko, F. Thrum, E. Il'ichev, and H.-G. Meyer, "High Tc SQUIDS with Two or Three Junctions for Application in Disturbed Environment." To be published in Appl. Supercond. Department of Cryoelectronics, Institute for Physical High Technology, P.O. Box 100239, D-07702 Jena, GERMANY.

V. Sokolovsky, M. Sinder, and V. Meerovich, "Response of High-Tc Superconductor to Time-Increasing Magnetic Field." To be published in Appl. Supercond. Department of Physics, Ben-Gurion University of the Negev, P.O. Box 653, 84105 Beer-Sheva, ISRAEL.

Masahide Takahama, Tomoko Goto, and Kazuo Watanabe, "Field Dependence of Jc for Melt Textured Filamentary Nd123 Superconductor." To be published in Physica C. Contact Tomoko Goto, Department of Materials Science and Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466, JAPAN; telephone +81 52 735 5265; telefax +81 52 735 5294; e-mail zwgoto@mse.nitech.ac.jp. Key words: filamentary Nd123 superconductor, transport Jc, magnetic field, flux pinning. 74.25.Ha; 74.72.Bk; 74.80.Bj; 85.25.Kx.

A. Trautner, D. Goehring, P. Haug, B. Sailer, A. Ehmann, W. Wischert, and S. Kemmler-Sack, "(Bi,Pb)-2223 Phase Formation in Ag Clad Tapes." Submitted to Phys. Stat. Solidi. Institut fuer Anorganische Chemie der Universitaet Tuebingen, Auf der Morgenstelle 18, D-72076 Tuebingen, GERMANY. 74.72.-h; 74.80.-g.

David Walker, Bruce A. Scott, Bai-Hao Chen, and Yanhui Wang, "Anatomy of High Pressure Synthesis Reactions in the Sr-Cu-O-Cl System." To be published in Physica C. Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964. Key words: high-pressure reactions, Sr-Cu-O-Cl system, phase composition.

G.V.M. Williams, J. L. Tallon, and J. W. Loram, "Crossover Temperatures in the Normal-State Phase Diagram of High-Tc Superconductors." Submitted to Phys. Rev. B. New Zealand Institute for Industrial Research, Gracefield Research Centre, Gracefield Road, P.O. Box 31310, Lower Hutt, NEW ZEALAND; J. L. Tallon's telefax +64 4 569 0117; e-mail j.tallon@irl.cri.nz. 74.25.Bt; 74.25.Dw; 74.62.Dh; 74.72.-h.

M. S. Wong and S. S. Wang, "Processing and Properties of Bi-2212 Whiskers Reinforced BPSCCO HTS Composite." Preprint #97:175; submitted to Supercond. Sci. & Technol. Department of Mechanical Engineering and 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. S. Wong, S. S. Wang, and I. G. Chen, "Top-Seeded Melt-Textured (Mg,O)w/YBa2Cu3O7-d Superconducting Composites: Microstructure, Superconducting, and Mechanical Properties." Preprint #97:176; submitted to Supercond. Sci. & Technol. Department of Mechanical Engineering and 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.

W. Wong-Ng, J. A. Kaduk, and W. Greenwood, "Crystal Structures and Reference X-ray Powder Diffraction Patterns of Sr4-xCaxPb2O8 (x=1,2,3)." To be published in Powder Diffraction. A215 MATLS, National Institute of Standards and Technology, Gaithersburg, MD 20899; telephone (301) 975-5791; telefax (301) 975-5334; e-mail wongng@tiber.nist.gov.

Winnie Wong-Ng, Brian Toby, and William Greenwood, "Crystallographic Studies of BaR2ZnO5 (R = La, Nd, Dy, Ho, Er and Y)." To be published in Powder Diffraction. A215 MATLS, National Institute of Standards and Technology, Gaithersburg, MD 20899; telephone (301) 975-5791; telefax (301) 975-5334; e-mail wongng@tiber.nist.gov.

Jinwu Ye, "Coulomb Interactions at Superconductor to Mott-Insulator Transition." Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218; e-mail jinwu@eta.pha.jhu.edu; preprint also available at cond-mat@xxx.lanl.gov (#9801005).

Dmitry Y. Zinoviev, "Design Issues in Ultra-Fast Ultra-Low-Power Superconductor Batcher-Banyan Switching Fabric Based on RSFQ Logic/Memory Family." To be published in Appl. Supercond. Departments of Physics and Astronomy and Computer Science, State University of New York, Stony Brook, NY 11794.

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

March 9 - 10, 1998: Defining the Advanced Technology Challenges of the Electronic Commerce Marketplace, National Institute of Standards and Technology, Gaithersburg, Maryland. Registration deadline, February 20, 1998. For registration information, contact Lori Phillips, Bldg. 101, Rm. B116, NIST, Gaithersburg, MD 20899-0001; telephone (301) 975-4513; telefax (301) 948-2067; e-mail lori.phillips@nist.gov. General information available at telephone (800) 287-3863; telefax 301-926-9524; Web site http://www.atp.nist.gov.

April 28 - May 2, 1998: NATO Advanced Research Workshop Symmetry and Pairing in Superconductors, Oreanda Hotel, Yalta (Crimea, Ukraine). Supported by NATO and co-sponsored by Ministry of Ukraine for Science and Technology. Main objective is to bring together experts of various fields of sciences on superconductivity. Discussions will include the status of symmetry and pairing conditions for low- and high-temperature superconductors, applications, and relevance to practical problems. Main topics include the following: mechanisms of superconductivity; symmetry of pairing, theory, and experiment; pseudogap; thermodynamics; fluctuations; heavy fermions; vortex dynamics; and applications. Abstract deadline, April 4, 1998. Proceedings of the Workshop will be published in a Kluwer series publication. For information contact S. Kruchinin, Bogolyubov Institute for Theoretical Physics, Metrologichna str. 14-b, 252143, Kiev, Ukraine; telephone +380 44 266 9468; telefax +380 44 266 5998; e-mail kruchitp@gluk.apc.org or sps98@nonlin.gluk.apc.org; Web site http://nonlin.gluk.apc.org/~sps98/.

Aug. 25 - 29, 1998: The 17th General Conference of the Condensed Matter Division of the European Physical Society (CMD-EPS 17), Grenoble, France. Conference will be coupled with Journees de la Matiere Condensee (JMC 6). Aim is to provide a forum where scientists (mostly from Europe) can present their research work in condensed-matter physics. Seven plenary sessions in the following topics: Si/Ge nanostructures, smart cut of Si, superconductivity, quantum friction, synchrotron radiation, biophysics, and neutron scattering. In addition, there will be 37 colloquia and 50 invited contributions in 5 parallel sessions. Abstract and student grant application deadline, March 15, 1998; early registration deadline, May 15, 1998. For information, contact Conference Secretariat, CMD17-JCM6, Laboratoire Louis Neel, BP 166 X, F-38042 Grenoble Cedex 9, France; telephone +33 4 76 88 90 02; telefax +33 4 76 88 90 04; e-mail (for information) cmd17@labs.polycnrs- gre.fr or e-mail (for abstract) abs17@labs.polycnrs-gre.fr; Web site http://www.polycnrs-gre.fr/eps.html.

Sept. 16 - 19, 1998: First International Conference on Inorganic Materials -- Synthesis, Characterization, Properties and Applications of Inorganic Materials, Palais des Congres de Versailles, France. Conference will cover of interest in inorganic materials that demonstrate unusual properties which may lead to new applications. Will comprise six sessions and two poster sessions. Contributions on the latest scientific and technological results will be supplemented by a number of high-level invited presentations and reviews by experts in these fields. Poster and oral contributions are invited in the following areas: Electronic Materials -- includes systems that exhibit superconductivity, colossal magnetoresistance, or that might find applications in batteries, sensors, or optical devices, etc.; Structural Materials and Ceramics -- includes materials that are used for high- temperature applications, composites, ferroelectrics, and materials that exhibit low dielectric or unusual temperature-dependent properties; Simulation of Inorganic Materials -- includes applications of both force-field methods and first-principle techniques to inorganic materials as well as the interplay between computer simulation and experiment; Biomaterials -- will include studies on biominerals, biomimetic systems, inorganic-based biosensors, and bioinspired materials; Porous Materials -- will include crystalline nanoporous materials such as zeolites and related phases, surfactant-mediated materials, and noncrystalline nanoporous inorganics. Official language is English. A table-top exhibition will be run in conjunction with the conference. For information, contact Sue Stewart, First International Conference on Inorganic Materials Secretariat, 4 Manor Farm Barns, Church Lane, Charlton-on-Otmoor, Kidlington, Oxon OX5 2UA, United Kingdom; telephone +44 1865 331040; telefax +44 1865 331125; e-mail 101515.2472@compuserve.com.

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

Nominations and applications are invited for the position of Executive Director of the Texas Center for Superconductivity at the University of Houston (TCSUH), to be filled by Fall 1998. TCSUH is an established, major international research and educational resource for high- temperature superconductivity (HTS) and related materials located in Houston, Texas. The Center's emphasis is on HTS and related materials synthesis, characterization, and application studies, as well as advanced education and public outreach. The Executive Director will serve as the Center's chief spokesperson. Specific responsibilities will include establishing the Center's research agenda to continue the development of a strong, broadly funded research and development program in HTS and related materials; overseeing a strong research team, drawing on existing researchers as well as new members; interfacing with academic programs in the education and training of graduate students; and vigorously promoting university/industry and university/government linkages. The position notice and additional information is available at http://www.uh.edu/tcsuh/announce/exec_dir.html.

FIG. 1. The SX Series[TM] Bipolar Current Lead System from EURUS Technologies, Inc. The current leads use bulk, sintered YBCO material.

(See this figure in the rtf or binhqx version of the Feb. 1 newsletter available at the HTCU 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, #3, February 1, 1998.