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

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Scanning SQUID Petrology

A new application for the scanning SQUID microscope is reported by B. A. Scott (Lamont-Doherty Earth Observatory and IBM-Yorktown) et al. in an article to be published in Nature. Using this instrument in combination with petrological techniques in a method called scanning SQUID petrology, the authors have imaged and identified low concentrations of superconducting phases in a complex phase assemblage. Here, the authors report that they studied a Sr2CuO3-KClO3 diffusion couple, prepared using high-pressure synthesis (60 kbar at 950^oC), and detected the superconductor Sr3Cu2O5Cl at the ~3% level adjacent to the KClO3. The authors note that scanning SQUID petrology has general applicability and is capable of detecting magnetic or superconducting phases at concentrations less than 1 ppm.

Hg Cuprates

As reported by L. Krusin-Elbaum (IBM-Yorktown) et al., the fission fragments resulting from 0.8 GeV proton-induced fission of Hg nuclei in superconducting HgBa2CaCu2O6+d (Hg-1212, Tc ~~ 120 K) produce strong- pinning, splayed columnar defects. After irradiation, the persistent current density J, determined from magnetic hysteresis using the TEM- determined grain size of ~20 micrometers, is enhanced by orders of magnitude in fields of 1-2 T, and the irreversibility line is extended to temperatures above 100 K (higher than in Y-, Bi-, or Tl-based materials). A large shift in the irreversibility temperature, Delta- T_[irr] ~ 25 K, is maintained up to a 5.5 T field. Since this method is not limited by the short penetration range of heavier particles or ions, the authors suggest that this method could enhance the performance of larger superconducting objects, such as magnets.

A paper by T. Tsuchiya and K. Fueki (Science University of Tokyo) reports the synthesis of single-phase HgBa2CaCu2O6+d (Hg-1212) using starting materials with HgO 16% in excess. The authors determined thermodynamic diagrams that show the stability domains of HgO and Hg- 1212. Using chemical analysis, the authors found that the valence of Hg is always 2+ but that the average valence of Cu changes with the oxygen content, with zero-resistance Tc changing from 122 K to 118 K as the oxygen content increases from 6.10 to 6.22.

Strongly overdoped HgBa2Ca2Cu3O8+d (Hg-1223) samples with superconducting transition at 97 K have been obtained by K. Fujinami (Tokyo Tech) et al. using HgO, Ca2CuO3, CuO, and mixtures of highly oxidized BaCuO_[2+epsilon] (epsilon ~~ 0.13) or BaO2 powders as starting materials for high-pressure synthesis at 5 GPa and 950^oC. The overdoped state was confirmed by observing negative values for the Seebeck coefficient throughout the temperature range from Tc to 320 K in a thermoelectric power measurement.

A paper by L. Jansen (ETH-Zurich) and R. Block (Amsterdam) reports an analysis of recent measurements of the effect of pressure on Tc of five samples of Hg2Ba2Y1-xCaxCu2O8-d. The authors report that all experimental results can be quantitatively interpreted in terms of indirect-exchange Cooper-pair formation via diamagnetic oxygen anions. In particular, the observed large increases in Tc (>=55 K) over the pressure range P = 0 to 20 GPa are reproduced.

Hole States

An experimental study of the dynamics of holes in the valence bands of zero-, one-, and two-dimensional undoped model cuprates, as expressed via the screening of a Cu 2p core hole, has been carried out by T. Boeske (Dresden) et al. High-quality single crystals of Bi2CuO4, Li2CuO2, Ba3Cu2O4Cl2, Sr2CuO3, SrCuO2, Sr2CuO2Cl2, and Ba2Cu3O4Cl2 were used. The authors found that the response depends strongly upon the dimensionality and the details of the Cu-O-Cu network geometry and that it clearly goes beyond the present theoretical state-of-the-art description within the three-band d-p model.

The unoccupied electronic structure of the layered cuprates of Sr2CuO2Cl2 and Ba2Cu3O4Cl2 has been studied by S. Haffner (Dresden) et al. using polarization-dependent x-ray absorption spectroscopy at the O 1s and Cu 2p_[3/2] edges and band-structure calculations within the local density approximation. In contrast to almost all high-temperature superconductors, in these oxychlorides there are no oxygen atoms outside the CuO2 planes. The authors assert that their results give the first direct experimental information regarding the oxygen-derived unoccupied electronic structure of undoped CuO2 planes in square-planar coordination.

Bi2Sr2Ca(NixCu1-x)2O8

According to a preprint by R. Movshovich (Los Alamos) et al., the high- temperature superconductor B2Sr2Ca(NixCu1-x)2O8 (Tc = 89 K for x = 0, 78 K for x = 0.006, 77 K for x = 0.015, and 74 K for x = 0.024) exhibits a low-temperature phase transition. This transition manifests itself as a sharp reduction of the thermal conductivity at a temperature Tc* ~~ 200 mK. The temperature dependence of the thermal conductivity changes dramatically from T^[alpha] with 1.6 < alpha < 1.75 above the transition to T-linear behavior below the transition. Application of a small magnetic field suppresses the low-temperature phase. The authors interpret this behavior as a phase transition into a second bulk low- temperature superconducting state in which time-reversal symmetry is likely to be broken. The authors stress that this discovery constitutes direct evidence for unconventional superconductivity in high-temperature superconductors.

Motivated by the above experiment, G. E. Volovik (Helsinki University of Technology and Landau Institute) considers superconductors in which time-inversion symmetry is broken and superconductivity is determined by not only the symmetry of the superconducting state but also the topology of the ground state. The author finds that superconducting states are described by an integer-valued momentum-space topological invariant N. The boundary separating domains with different N (N_2 not equal to N_1) contains fermion zero modes. These fermions are current-carrying and produce nonzero current along the domain wall in the ground state if N_2 is not equal to N_1.

Other Bi Cuprates

The effects of Pb substitution in single crystals of the high- temperature superconductor Bi2Sr2CaCu2O8+d (Bi-2212) have been studied by C. Kendziora et al. (NRL). The authors compared the Pb-substituted samples with unsubstituted ones in terms of structure, cation composition, and the temperature dependencies of ac susceptibility and Raman scattering. The authors found that Pb^[2+] primarily substitutes for Bi^[3+], leading directly to a Tc reduction characteristic of overdoped samples.

According to a preprint by J. Koetzler and M. Kaufmann (Hamburg), the ac conductivity along the CuO2 layers of epitaxial films and single crystals of thickness 0.2 micrometer <= L_z <= 130 micrometers reveals clear signatures for 2D ordering. In particular, at Tc the screening length assumes the universal value L_zLambda(Tc)/2[nu]_s predicted by the Kosterlitz-Thouless theory, which indicates that binding of long vortex strings nucleates long-range superconductivity in samples containing up to 10^5 CuO2 layers.

Conductivity measurements near Tc in granular Bi1.6Pb0.4Sr2CaCu2O8+d [(Bi,Pb)-2212] and Bi1.6Pb0.4Sr2Ca2Cu3O10+d [(Bi,Pb)-2223] samples have been carried out by A. R. Jurelo (UFRGS, Porto Alegre) et al. The authors find that the resistive transition is a two-step process involving fluctuations at both the microscopic and mesoscopic levels.

A preprint by C. Rasmussen and S. K. Olsen (Technical University of Denmark) reports transport ac losses of Ag-sheathed Bi2Sr2Ca2Cu3O10+d (Bi-2223) tape conductors in the form of cables for power transmission lines operating at 77 K. Three conductors of length 1.0 m were constructed and tested. With the goal of achieving a conductor in which each tape had the same impedance and thus would carry the same current, the authors produced one cable with transposed tapes.

Measurements of the loss component chi" of the ac susceptibility of monofilament Bi-2223/Ag tape in a perpendicular ac magnetic field are reported by N. Savvides and K.-H. Mueller (CSIRO). The measurements were carried out as a function of temperature and ac magnetic-field amplitude in the range 0.02 mT to 7 mT at different frequencies in the range 5 Hz to 5 kHz. The ac loss is composed of an eddy-current loss in the silver sheath and a hysteretic loss in the superconducting core.

Measurements of chi" in monofilament and multifilament Ag-sheathed (Bi,Pb)-2223 samples with similar transport critical current values I_c at 77 K are reported by M. Lelovic (Pittsburgh) et al. The authors found that the multifilament samples exhibited higher losses than the monofilament samples under the same conditions. The authors discuss the loss peaks in terms of intergranular, intragranular, and eddy-current losses.

A preprint by N. Savvides et al. (CSIRO) reports measurements of the effects of bend strain epsilon on the critical current I_c(77K) of a 27- filament Bi-2223/Ag tape. The authors found that the irreversible strain limit epsilon_[irr] decreases from 0.4% for single-band tests to 0.2% for double-bend tests. At 0.4% strain, I_{c[epsilon]}/I_[c0] = 95% for single-bend tests and 60% for double-bend tests.

According to G. Z. Zhang et al. (TCSUH), the strain tolerance of the critical current density in bulk monolithic (Bi,Pb)-2223 is improved when the (Bi,Pb)-2223 is reinforced with MgO whiskers.

Measurements of the effects of shock loading on the critical current density of Bi-2223/Ag tapes have been carried out by S. J. Powell (Socorro) et al. The shocked samples showed a degradation of transport- current properties but maintained their high transition temperatures.

RBa2Cu3O7-d

Systematic investigations of the in-plane penetration depth lambda_[ab](T) of YBa2Cu3O7-d (d = 0.0, 0.3 and 0.43) have been carried out by C. Panagopoulos et al. (IRC-Cambridge). In comparing these results with those in HgBa2CuO4+d (Hg-1201) and HgBa2Ca2Cu3O8+d (Hg- 1223), the authors found that lambda_[ab](T) varies linearly with T, independent of crystal symmetry, anisotropy, carrier concentration, and number of CuO2 planes per unit cell, but its slope, obtained from plots of 1-[lambda_[ab](0)/lambda_[ab](T)]^2 vs. T, scales with 1/Tc. The authors note that their penetration-depth data are in agreement with mean-field theory for a weak-coupling d-wave superconductor for which Delta_0/k_BTc ~~ 2.

Measurements of the intensity of the [63]^Cu NQR and quadrupolar satellite NMR at elevated temperatures are reported by S. P. Klein et al. (Oregon State) for the planar Cu(2) sites in samples of nominal composition YBa2Cu3O7. The authors found that spin-echo intensities decrease dramatically as the temperature increases from room temperature to 500 K and that the onset of intensity loss occurs at lower temperatures in more defective samples. The authors attribute the observed effects to motion of chain-oxygen atoms in the Cu(1) layer. These motions occur on the time scale of the order of 10 microseconds at 500 K, where thermally generated defects dominate. At lower temperatures, the dependence on defect concentration is strong.

Previous studies on the high-Tc superconductor Tl2Ba2CuO6+d (Tl-2201) have given evidence for distinct low- and high-temperature oxygen- ordering processes activated for temperatures above 13 K and 200 K, respectively. Experiments by S. Sadewasser (Washington University) et al. on strongly underdoped YBa2Cu3O6.41 with Tc ~~ 13 K, however, reveal only high-temperature relaxation processes with a relaxation time tau at 298 K which increases under pressure from approximately 10 h at 1 bar to 50 h at 0.79 GPa and 550 h at 2.3 GPa. From these results the authors find the activation volume to be 4.2 cm^3/mol, a value equal to 3/4 of the molar volume of the O^[2-] ion.

The thermoelectric power S has been measured by C. Sulkowski (Wroclaw) et al. for a series of RBa2Cu3O7-d (R = Y, Gd, and Dy) single crystals along the ab plane and the c direction. The doping level of these crystals varied from highly underdoped (Tc = 44 K) through optimally doped (Tc = 90 K) to slightly overdoped (Tc = 88 K). Both S_[ab] and S_c changed linearly with the doping level, but S_[ab] was found to change sign near optimal doping, as observed for polycrystalline materials, while S_c remained positive for the whole series.

A preprint by J. Hauck et al. (Juelich) reports MOx pseudobinary phase diagrams with M = Nd2Cu, Nd1.85Ce0.15Cu, La1.13Ba1.87Cu3, PrBa2Cu3, NdBa2Cu3, YBa2Cu3, and Ca2Ba2Cu4, which give the temperature and oxygen partial pressure to synthesize compounds with defined oxygen content x, grow single crystals, or optimize the melt-texture process. The authors report that the superconducting phases Nd1.85Ce0.15CuO4, La1.13Ba1.87Cu3O7, PrBa2Cu3O7, NdBa2Cu3O7, YBa2Cu3O7, and Ca2Ba2Cu4O9 are metastable.

A paper by C.-J. Kim (KAERI) et al. reports the influence of oxygen annealing on the levitation force for melt-textured multidomain YBa2Cu3O7-d samples cooled with (FC) and without (ZFC) magnetic field. The variation of the levitation force vs. oxygen annealing time is explained in terms of the microstructure developed during oxygen annealing.

The temperature dependence of the electrical resistivity of YBa2- xCaxCu3O7-d (0 <= x <= 2) has been measured by M. K. Chattopadhyay (Kharagpur) et al. The authors report a metal-insulator transition, accompanied by a six order-of-magnitude increase in resistivity as x varies from 0 to 2.

To model the field dependence of the critical current density Jc(B) in RBCO samples with a secondary or fishtail peak in the magnetization, T. H. Johansen et al. (Oslo) have introduced a model Jc(B) consisting of two terms: a Kim-model contribution to describe the low-field magnetization peak and a Lorentzian contribution to describe the fishtail peak. The authors show that measured magnetization loops of NdBa2Cu3O7-d samples with a pronounced fishtail peak are well fitted by this model, and that Jc(B) can be determined accurately without invoking the Bean model (constant Jc), thus avoiding an inconsistency in the analysis.

Other Cuprates

The magnetic ordering of Er ions in Er2Ba4Cu7O15-d (d = 0.08 and 0.7) has been studied by G. Boettger (ETH-Zurich and PSI) et al. via low- temperature heat-capacity measurements. An anisotropic two-dimensional (2D) Ising model was found to describe the experimental data for Er2Ba4Cu7O14.92, while a model consisting of 1D Ising chains and 2D Ising clusters of Er^[3+] ions was required to fit the specific-heat data of Er2Ba4Cu7O14.3.

Low-energy magnetic excitations in Nd2-xCexCuO4 with 0 <= x <= 0.2 have been investigated by E. Maiser (Karlsruhe) et al. using measurements of the specific heat. For all Ce-doped samples (x >= 0.05), a linear term gammaT was found at very low temperatures (T <= 0.5 K), with 0.3 J/K^2 <= gamma <= 0.6 J/K^2 per mole Nd for 0.05 <= x < 0.14 and 3 J/K^2 <= gamma <= 4 J/K^2 per mole Nd for higher Ce concentrations.

The interaction of an Abrikosov vortex lattice with randomly placed strong pinning centers (produced experimentally by heavy-ion irradiation) has been modeled by K. E. Gray (Argonne) et al. using a simple but powerful expression. The authors find excellent quantitative fits to the dissipation in ion-irradiated Tl2Ba2CaCu2O8+d (Tl-2212) for T/Tc = 0.75-0.9 over ranges of 10^4 in resistance and 60 in field. The three free parameters are within a factor of two of expectations.

As reported by S. Adachi et al. (SRL-ISTEC), superconducting La2CuO4-dFy samples have been synthesized by heating La2CuO4 together with the fluorinating reagent NH4F at 240^oC in flowing oxygen gas. Bulk superconductivity with Tc = 42 K in the samples was confirmed by dc magnetic susceptibility measurements.

High-resolution powder x-ray diffraction results on Pb2Sr2Y1-xCaxCu3O8+d have been obtained by U. Staub (PSI) et al. The authors found that hkl reflections with both h and l nonzero were distinctly broader than the others. A model based on anisotropic distributions of the d spacings within the ac plane, corresponding to fluctuations resulting from oxygen nonstoichiometry, can explain the observations.

A paper by Y. T. Zhu (Los Alamos) et al. reports experiments on varying the oxygen content of cubic YBa4Cu3O8.5+d (Y-143) from 8.6 to 9.1 in hopes of making it superconductive. Alas, the Y-143 phase was found to be nonsuperconducting for all annealing conditions.

Vortices

The properties of Josephson vortices in stacked intrinsic Josephson junctions, such as in Bi2Sr2CaCu2O8+d (Bi-2212), have been examined theoretically and experimentally by V. M. Krasnov (Chalmers and ISSP- Chernogolovka) et al. The authors find that the critical current Jc perpendicular to the layers can be multiple-valued because of the possibility of having different fluxon configurations or modes. The fluxon self energy, lower critical field H_[c1], and the temperature and magnetic-field dependencies of Jc were calculated for a stack with nonidentical junctions. A related paper by V. M. Krasnov and D. Winkler (Chalmers) reports a theoretical study of the static and dynamic properties of stacked Josephson junctions and presents an approximate analytic solution for a stack with arbitrary junction parameters. The authors conclude that since different modes with equal total number of fluxons are not identical, the total possible number of flux-flow branches in the current-voltage characteristics can be much larger than the number of junctions in the stack.

The influence of weak links upon the surface resistance of superconductors has been modeled by J. McDonald and J. R. Clem (Ames Lab, Iowa State). The authors present numerical solutions for both small junctions and long uniform junctions, and they point out both similarities and significant differences between the two cases.

Two papers by T. B. Doyle (Natal) et al. report on details of the local magnetization in disk-shaped specimens. One of these presents an analysis of the local flux density (B), field (H), and magnetization (M) vs. the radial coordinate for fields near the vortex-lattice-melting transition of Bi2Sr2CaCu2O8+d (Bi-2212). The other paper accounts for both the geometrical barrier and bulk pinning to describe the magnetization curves of Bi-2212 samples exhibiting a pronounced second peak, or arrowhead anomaly, in the magnetization.

A paper by M. Amirfeiz et al. (Genova) reports measurements of the magnetoresistivity and Hall effect on a YBCO epitaxial film as a function of the angle between the external magnetic field and the c axis. The data disagree with theoretically proposed angular scaling rules, and the authors attribute the disagreement to changes in vortex structure due to the layered crystal structure.

A theory of the Hall anomaly in the mixed state of superconductors (sign change of the Hall resistivity) has been developed by P. Ao (Umea). The author proposes that this anomaly is due to the competition between vortex vacancies and interstitials. The author obtains the vacancy formation energy and a scaling relation between the Hall and longitudinal resistivities with the power varying between 1 and 2 depending on sample details. Near the superconducting transition temperature and for small magnetic fields, the author finds that the Hall conductivity is proportional to the inverse of the magnetic field and to (Tc-T)^2.

A preprint by X.-M. Zhu and P. Ao (Umea) discusses calculations of the transverse force on vortices and points out how the relaxation-time approximation can lead to incorrect results.

Theory

The large-scale dynamics of vortex lattices and charge-density waves driven in a disordered potential are analyzed by S. Scheidl (Koeln and Argonne) and V. M. Vinokur (Argonne). Using a perturbative coarse- graining procedure, the authors present an explicit derivation of nonequilibrium terms in the renormalized equation of motion, in particular Kardar-Parisi-Zhang nonlinearities and dynamic strain terms.

The problem of the vortex contribution to the thermal properties of dirty d-wave superconductors has been considered by C. Kuebert and P. J. Hirschfeld (Florida). The authors find that in the clean limit, the main contribution to the density of states in a d-wave superconductor arises from extended quasiparticle states which may be treated semiclassically, giving rise to a specific heat contribution delta-C(H) ~ H^[1/2]. The authors find that the extended states continue to dominate in the dirty limit but lead to an H log H behavior at the lowest fields. The authors also discuss the range of validity of recent predictions of scaling with H^[1/2]/T in real samples.

A self-consistent treatment of pinhole junctions in d_[x^2-y^2] superconductors has been developed by M. Fogelstroem (Northwestern and Abo) et al. The authors study the nonsinusoidal current-phase relation at different temperatures and different angles between the crystal axes and the junction (surface) normal. The authors also show that the Josephson-energy minima and maxima in general do not lie at 0 and pi, which can explain the origin of spontaneous currents and associated magnetic flux much less than the flux quantum phi_0 = h/2e at grain boundaries.

A microscopic theory of the ac Josephson effect in short ballistic superconducting constrictions with arbitrary electron transparency and in constrictions with diffusive electron transport has been developed by A. V. Zaitsev (IRE-Moscow) and D. V. Averin (SUNY-Stony Brook). As applications of the theory, the authors studied time-dependent and dc currents in constrictions between superconductors with pair-breaking effects, and between normal conductors with proximity-induced superconductivity.

A preprint by C.-H. Pao (National Chung Cheng) and H.-B. Schuettler (Georgia) reports a study of the d-wave pairing instability in the two- dimensional Holstein-Hubbard model. The authors use the full fluctuation exchange approximation, which treats both Coulomb and electron-phonon interactions diagrammatically on an equal footing. The authors find that the isotope exponent alpha in this model is negative and small in comparison with either the classical BCS value of 1/2 or typical observed values in nonoptimally doped cuprate superconductors.

The temperature dependence of the spin susceptibility in YBa2Cu4O8 has been calculated by I. Eremin (Kazan State) et al. using the assumption that a pseudogap in the normal state opens because of a charge-density- wave (CDW) instability. The authors find good agreement with experiment. The model predicts both an isotope effect of the CDW- forming temperature and peculiar features of the Fermi surface.

A preprint by V. P. Gusynin (Kiev) et al. discusses the crossover in the superconducting transition between BCS- and Bose-like behavior for the simplest 2D model with s-wave nonretarded attractive interaction. The authors propose an interpretation of phenomena caused by doping, and they predict that pseudogap phase formation occurs as a new thermodynamic equilibrium normal state of a low-dimensional conducting electronic system.

The problem of two holes in the presence of strong antiferromagnetic fluctuations has been addressed by J. Riera (Rosario) and E. Dagotto (Florida State) using computational techniques. The authors report calculations of two-dimensional clusters and two-leg ladders using the Lanczos and truncated Lanczos algorithms on lattices with up to 2 x 16 and sqrt[32] x sqrt[32] sites.

A method to improve the accuracy of approximate techniques for correlated electrons that use reduced Hilbert spaces is proposed by E. Dagotto (Florida State) et al. As a first step, the method involves a change of basis that incorporates exactly part of the short-distance interactions. Although the method so far has been tested only on ladder systems, the authors note that the idea is general and should be applicable to a wide variety of problems.

A theory of electronic Raman scattering in nearly antiferromagnetic Fermi liquids has been constructed by T. P. Devereaux (George Washington) and A. P. Kampf (Augsburg) using the phenomenological electron-electron interaction introduced by Millis, Monien, and Pines. The authors highlight the role of hot spots and their resulting signatures in the channel-dependent Raman spectra, and different scaling regimes are addressed. The authors compare the theoretical results with Raman spectra taken in the normal state of overdoped Bi2Sr2CaCu2O8+d, and they find that many features of the symmetry-dependent spectra can be explained by the theory.

Using the model of polar singlet-triplet Jahn-Teller centers, A. S. Moskvin and A. S. Ovchinnikov (Ural State) have obtained the cross section for magnetic neutron scattering in high-Tc cuprates.

Thin Films

The nonlinear microwave response of superconducting YBCO thin films and crystals has been studied by G. Hampel (Bell Labs) et al. by measuring the third-order harmonic amplitude E_{3[omega]}. The authors found E{3[omega]} to be dominated by two extrinsic effects: (a) the interaction with flux lines in weak links, leading to an increased nonlinear response at low temperatures and (b) rf-related flux-line creation at film edges, yielding a high E{3[omega]} signal close to Tc. Both effects together lead to a minimum in E{3[omega]} around 40-60 K, which makes this temperature interval interesting for rf applications. Intrinsic nonlinearities are smaller by orders of magnitude and could not be detected.

A preprint by B. A. Willemsen (Superconductor Technologies) et al. presents experimental results for microwave intermodulation in a series of superconducting hairpin resonators. The authors found that geometry plays a dominant role in determining both the losses and intermodulation in these resonators.

The ac susceptibility (chi'+ichi") of a YBCO thin film in a perpendicular ac magnetic field H_a of amplitude 0.22-30.8 Oe has been measured by G. C. Han (Singapore) et al. as a function of temperature. The authors found that chi' and chi" vs. temperature T for various H_a can be scaled onto single curves using the chi" peak value chi_p" and the corresponding temperature T_p as scaling parameters.

The development of a flame-spraying technique to produce YBCO targets that can be used for the deposition of YBCO thin films by magnetron sputtering is described in a preprint by I. Van Driessche et al. (Gent).

Applications

A 1.2 MVA HTS-based fault-current limiter (FCL) was built last year by ABB and since November 1996 has been undergoing a one-year endurance test in the auxiliary line of a Swiss hydropower plant. It is the first high-Tc superconducting device to be tested in a power plant under actual operating conditions. Two preprints regarding the FCL are listed in this issue. A paper by W. Paul (ABB) et al. describes the design, fabrication, and testing of the prototype FCL. It is a three-phase device, based on a shielded iron core concept, using stacks of superconducting Bi-2212 rings, which are fabricated by a partial-melt process. A paper by M. Chen et al. (ABB) describes the processing of these rings, which are 38 cm in diameter. The rings show an onset Tc of 96 K and a typical Jc of 1.5 x 10^3 A/cm^2 with I_c = 2.5 kA.

The deposition of high-quality, large-area superconducting YBa2Cu3O7-d films onto 2" diameter substrates by pulsed laser deposition (PLD) is described in a preprint by R.C.Y. Auyeung (Sachs Freeman Associates) et al. The PLD system makes use of a novel pseudo-blackbody radiation heater. YBCO films deposited onto both sides of a 1" square by 0.010" MgO substrate were patterned and fabricated into a four-channel microwave receiver operating near 10 GHz. The receiver exhibited low loss and good frequency selectivity at 77 K.

Other Activities

Experiments by N. Li (NASA Marshall Space Flight Center) et al. have been carried out to search for gravitational shielding effects of superconductors reported by E. Podkletnov and R. Nieminen [Physica C 203, 441 (1992)]. The new experiments, which have a sensitivity four or five orders of magnitude better than those of the earlier experiments, do not show any gravitational shielding within experimental error. The maximum contribution to a change in gravity above a static YBCO superconductor in a constant magnetic field was measured to be less than 2 parts in 10^8 of the normal gravitational acceleration.

The quasiparticle energy relaxation rate tau_[epsilon]^[-1] in the cuprate superconductors La1.85Sr0.15CuO4-x and YBa2Cu3O7-d has been studied experimentally by S. G. Doettinger (Stanford) et al. The authors obtained tau_[epsilon]^[-1] from measurements of the critical vortex velocity v_[phi]*, where the current-voltage characteristics have a sharp kink, and found that tau_[epsilon]^[-1] proportional to exp[- 2[Delta](T)/k_BT], suggesting that the electron-electron recombination process, perhaps in combination with the emission of another excitation, is crucial.

A preprint by M. V. Simkin (Brown) reports numerical simulations indicating that the resistivity of a fully frustrated 2D Josephson- junction array is due to motion of domain walls in a vortex lattice, rather than to motion of single vortices.

The time dependence of magnetic-flux penetration into YBCO tubes subjected to a sudden applied magnetic field step has been studied theoretically and experimentally by H. Castro (Lausanne) et al. The results could be applied to the behavior of fault-current limiters and other fast-switching devices.

A preprint by M. Houssa and M. Ausloos (Liege) theoretically analyzes the field dependence of the thermal conductivity kappa of single crystals of the heavy-fermion superconductor UPt3 for magnetic fields applied along the basal (ab) plane and along the c axis. The authors calculate the effect of heat-carrying electrons scattered by quasiparticle excitations in the vortex cores for an anisotropic gap parameter of either E_[1g] or E_[2u] symmetry. Comparison with recent experimental results of H. Suderow et al. [J. Low Temp. Phys. 108, 11 (1997)] favors the E_[2u] gap parameter, i.e., with linear lines of nodes along the basal plane and quadratic point nodes along the c axis.

Overviews

The theory of the ac Josephson effect and noise in superconducting constrictions is the subject of a book chapter by D. V. Averin (SUNY- Stony Brook). The author discusses the importance of multiple Andreev reflections and how these are manifested in the sub-harmonic gap structure in the current-voltage characteristics of superconducting point contacts (56 refs.).

A review chapter on lattice instabilities and the appearance of several phases in YBa2Cu3Ox and Y1-yCayBa2Cu3Ox has been prepared by E. Kaldis (ETH-Zurich). Using near-equilibrium samples of high purity and homogeneity and an oxygen determination method with high resolution, at least one phase transition was found in the oxygens of the superconducting planes with the help of x-ray and neutron diffraction (44 refs.).

Recent developments in the theory of vortices in superfluids and superconductors are reviewed by D. J. Thouless (Washington) et al., who discuss why the dynamics of vortices is important and why some key results are still controversial. The authors argue for a Magnus force that is proportional to the superfluid density, and they find that the effective mass density of a vortex in a neutral superfluid is divergent at low frequencies (27 refs.).

A lecture by D. Pines (Los Alamos National Laboratory and Illinois- Urbana) describes how far we have come in the past ten years to understanding high-temperature superconductivity, and he discusses the prospects for the development of a microscopic theory. The author argues that the magnetic interaction between planar quasiparticle interactions is responsible for the normal-state behavior and the appearance of superconductivity at high temperature.

Ph.D. Theses

The design, construction, and analysis of a 1/5-scale model high- temperature superconducting magnet coil test facility for Maglev (magnetic levitation) is discussed in the MIT Ph.D. thesis of M. T. Thompson. The test fixture allowed low-friction motion of levitating magnets, simulating the vertical movement of a Maglev train under external disturbances. A multiple-loop guideway was built and tested, and lift, drag, and guidance forces were measured at operating speeds approaching those of an actual high-speed train (301 refs.).

The microstructure-physical property relationships of oxide thin films and multilayers heteroepitaxially grown on different crystalline substrates have been studied in the Ph.D. thesis of A. Vailionis (Royal Institute of Technology, Stockholm). The author applied both extended x-ray absorption fine structure (EXAFS) and a one-dimensional kinematic x-ray diffraction model to study the thin-film microstructural properties of Bi2Sr2CuO6 (Bi-2201), Bi2Sr2CaCu2O8+d (Bi-2212), Bi2Sr2Ca2Cu3O10+d (Bi-2223), Bi2Sr2Can-1CunOx with n = 8, 9, 10, and 11, infinite-layer Ca1-xSrxCuO2, and HgBa2CaCu2O6+d (Hg-1212) (269 refs.).

The synthesis, structure, and superconducting properties of Bi cuprates in the Bi2Sr2CaCu2O8+d (Bi-2212) and Bi2Sr2Ca2Cu3O10+d (Bi-2223) families were studied in the Tuebingen Ph.D. thesis of J. Glaser. Included in this work are studies of the effects of substitutions and of heat-treatment temperatures and atmospheres (109 refs.).

Contributed by John R. Clem

Contents: Technology News begins on page 8; Preprints begin on page 9; Coming Events begin on page 16; Resources are on page 17; and an important renewal notice is on page 17.

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.

At this year's Cryogenic Engineering Conference in Portland, Oregon, EURUS Technologies Inc. displayed a two-kilometer silver-sheathed Bi- 2223 tape designed for use in ac and dc power transmission cables, fault current limiters, magnetic separation devices, and various other superconductive coil windings. At under twenty dollars per meter, the EURUS HTS tape is accessible to business and research groups who can use it to cost justify their superconducting product developments.

EURUS also recently announced its acquisition of Plastronic Inc., a Midwest developer and manufacturer of HTS tape; the purchase is one in a series of commercial HTS technologies acquired by the company. EURUS physicists and engineers are conducting a redesign effort aimed at improvement of the materials to be utilized in the HTS tape, and following the comprehensive design review, EURUS will launch manufacturing of the new HTS tape to be called Power Plus(TM) at Innovation Park, near the National Magnetic Field Laboratory in Tallahassee, Fla. For further information, contact 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.

In other news from the company, the SL Series(TM) power leads manufactured by EURUS, Inc. have a multi-fiber superconducting conductor with parallel conducting paths, and features the superconducting fibers encapsulated in a proprietary compound for mechanical and thermal stability as well as protection against chemical and environmental damage. The electrical contacts use the EURUS, Inc. SuperSolder(TM), a superconducting adhesive alloy used for minimum contact resistance. The SL Series(TM) leads are now commercially available. For information, contact Sanford Cohen, Director -- Sales and Marketing, 2031 E. Paul Dirac Drive, Innovation Park, Tallahassee, FL 32310; telephone (904) 574-1800; telefax (904) 574-2998; e-mail info@teameurus.com.

The second commercial product in its superconducting magnetic energy storage (SMES) product line was announced by American Superconductor upon its first international sale of the SMES PQ VR System to Eskom, Africa's largest electricity supplier, and installed at the South Africa Pulp and Paper Industry (SAPPI) paper mill located in Stanger, South Africa. The introduction of the PQ VR, developed by Superconductivity, Inc. (SI), a subsidiary of American Superconductor, comes on the heels of the company's commercial launch of the first product in its SMES line, the PQ DC system now in operation at Tinker Air Force Base in Oklahoma City and at Cyanco, an industrial manufacturer of cyanide in Nevada. The PQ VR uses an energy storage magnet coil made from low- temperature superconducting wire, and is capable of being quickly charged and discharged indefinitely without degradation. The power electronics component of the PQ VR represents a significant breakthrough in the ability to actively insert power into the electrical line without breaking the utility connection. The entire PQ VR system is monitored remotely by Eskom and from Superconductivity, Inc.'s facility in Madison, Wis. The system is designed for voltage regulation in ac environments for manufacturing applications and provides supplemental ac power when voltage from incoming power lines drops below required levels for industrial equipment. The PQ DC system inserts power into the dc line of motor drives and uninterruptable power supplies. For further information contact Marianne Sabella or Kim Miller, FitzGerald Communications Inc., telephone (617) 494-9500; or American Superconductor Corporation, Two Technology Drive, Westborough, MA 01581; telephone (508) 836-4200; telefax (508) 836-4248.

At the Personal Communications Showcase (PCS'97) in Dallas, Texas, Conductus, Inc., displayed what it believes to be the first superconducting filter subsystem in a high-density, six-sector receiver. The new subsystem is an extension of the Clearsite(TM) platform and is designed to maximize network quality of service in dense urban environments. The subsystem includes twelve superconducting interference-reduction receive filters and twelve cryogenically cooled low-noise amplifiers as well as three transmit filters. Both tower mount and equipment-room configurations come equipped with a reliable closed-cycle Gifford-McMahon compressor/refrigeration unit. For further information, contact Stephen M. Garrison, Product Marketing Manager, Conductus, Inc., 969 West Maude Ave., Sunnyvale, CA 94086; telephone (408) 523-9430; telefax (408) 523-9999.

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.

S. Adachi, X.-J. Wu, T. Tamura, T. Tatsuki, A. Tokiwa-Yamamoto, and K. Tanabe, "Synthesis and Superconducting Properties of Fluorinated La2CuO4 Using NH4F." To be published in Physica C. Superconductivity Research Laboratory, International Superconductivity Technology Center (ISTEC), 10-13 Shinonome 1-chome, Koto-ku, Tokyo 135, JAPAN; telephone +81 3 3536-5703 through -5705; telefax +81 3 3536-5714 or -5717.

M. Amirfeiz, M. R. Cimberle, C. Ferdeghini, E. Giannini, G. Grassano, D. Marre, M. Putti, and A. S. Siri, "Angular Dependence of Magnetoresistivity and Hall Effect in a YBa2Cu3Ox Thin Film." To be published in Physica C (in press). Contact M. R. Cimberle, CNR/INFM, Department of Physics, University of Genova, via Dodecaneso 33, I-16145 Genova, ITALY; telephone +39 10 35 36 448; telefax +39 10 36 22 790; e- mail cimberle@genova.infn.it. Key words: magnetoresistivity, Hall effect, angular dependence. 74.76.-w; 74.25.Fy; 74.80.Dm.

P. Ao, "Theory of Hall Anomaly in the Mixed State," Department of Theoretical Physics, Umea University, S-901 87 Umea, SWEDEN.

R.C.Y. Auyeung, J. S. Horwitz, L. A. Knauss, and D. B. Chrisey, "In-Situ Pulsed Laser Deposition of Large-Area Ceramic and Multilayer Films for Applications in Industry." To be published in Rev. Sci. Instrum. Code 6672, Naval Research Laboratory, Washington, DC 20375-5345; telephone (202) 404-4144.

Dmitri V. Averin, "Theory of ac Josephson Effect and Noise in Superconducting Constrictions." To be published in Phys. and Appl. of Mesoscopic Josephson Junctions, edited by H. Ohta and C. Ishii (Universal Academy Press, Tokyo, 1997). Department of Physics, State University of New York at Stony Brook, Stony Brook, NY 11794.

T. Boeske, K. Maiti, O. Knauff, K. Ruck, M. S. Golden, G. Krabbes, J. Fink, T. Osafune, N. Motoyama, H. Eisaki, and S. Uchida, "Cu-O Network Dependent Core Hole Screening in Low-Dimensional Cuprate Systems: A High-Resolution X-ray Photoemission Study." Submitted to Phys. Rev. Lett. Institut fuer Festkoerper- und Werkstofforschung Dresden, Postfach 270016, D-01171 Dresden, GERMANY. 74.72.Jt; 71.27.+a; 74.25.Jb.

G. Boettger, P. Allenspach, A. Doenni, Y. Aoki, and H. Sato, "Low- Temperature Specific Heat of Er2Ba4Cu7O15-d." To be published in Z. Phys. B. Laboratory for Neutron Scattering, Eidgenoessische Technische Hochschule Zurich & Paul Scherrer Institute, Bldg. WHGA/131, CH-5232 Villigen PSI, SWITZERLAND; telephone +41 56 310 4374; telefax +41 56 310 2939; e-mail grit.boettger@psi.ch. 74.72.-h; 75.40.-s.

G. Boettger, J. Mesot, P. Fischer, and A. Furrer, "Ca Substitution in RBa2Cu3O7-d (R = Y, Er; d < 0.15): The Influence on Structure and Superconductivity." To be published in Physica B (in press). Laboratory for Neutron Scattering, Eidgenoessische Technische Hochschule Zurich & Paul Scherrer Institute, Bldg. WHGA/131, CH-5232 Villigen PSI, SWITZERLAND; telephone +41 56 310 4374; telefax +41 56 310 2939; e-mail grit.boettger@psi.ch. Key words: high-Tc superconductors, powder diffraction, Rietveld refinement, crystal fields.

H. Castro, L. Rinderer, E. Holguin, and J.-F. Loude, "Dynamics of Fast Flux Penetration in High-Tc Superconductors." To be published in Physica C (in press). Institut de Physique Experimentale, Universite de Lausanne, CH-1015 Lausanne, SWITZERLAND; telefax +41 21 692 3605; e-mail hcastro@ipe.unil.ch. Key words: high-temperature superconductors, flux flow, flux diffusion, magnetic response, ceramic materials.

M. K. Chattopadhyay, S. K. Ghatak, and T. K. Dey, "Metal-Insulator Transition in YBa2-xCaxCu3O7-d." To be published in Physica C (in press). Contact T. K. Dey, High Temperature Superconductivity Laboratory, Cryogenic Engineering Centre, Indian Institute of Technology, Kharagpur 721302, INDIA; telephone +91 3222 55221, ext. 77390; telefax +91 3222 55303; e-mail tapasdey@hijli.iitkgp.ernet.in.

Makan Chen, Thomas Baumann, Peter Unternaehrer, and Willi Paul, "Fabrication and Characterization of Superconducting Rings for Fault Current Limiter Application." To be published in Physica C: Proc. of the 5th Int. Conf. on Mater. and Mech. of Supercond. -- High-Temp. Supercond. (M^2S-HTSC V), Beijing, People's Republic of China, Feb. 28- Mar. 4, 1997. Dept. CHCRC.V4, ABB Corporate Research. CH-5405 Baden- Daettwil, SWITZERLAND; telephone +41 56 486-8008 or -8146; telefax +41 56 486-7314; Willi Paul's e-mail willi.paul@chcrc.abb.ch. Key words: Bi-2212, ceramic components, superconducting rings, current limiter.

E. Dagotto, G. B. Martins, J. Piekarewicz, J. Riera, and J. R. Shepard, "Diagonalization in Reduced Hilbert Spaces Using a Systematically Improved Basis." National High Magnetic Field Laboratory and Department of Physics, Florida State University, Tallahassee, FL 32306; preprint also available at cond-mat@xxx.lanl.gov (#9707205). 02.70.-c; 75.10.Jm; 75.40.Mg.

E. Dagotto, S. Yunoki, A. L. Malvezzi, A. Moreo, J. Hu, S. Capponi, D. Poilblanc, and N. Furukawa, "The Ferromagnetic Kondo Model for Manganites: Phase Diagram and Charge Segregation Effects." National High Magnetic Field Laboratory and Department of Physics, Florida State University, Tallahassee, FL 32306; preprint also available at cond- mat@xxx.lanl.gov (#9709029).

A. Del Vecchio, L. Mirenghi, L. Tapfer, C. Aruta, G. Petrocelli, and G. Balestrino, "Strain Analysis and Structural Characterization of SrCuO2/CaCuO2 Infinite Layer Superlattices." To be published in Physica C (in press). Contact L. Tapfer, Centro Nazionale Ricerca e Sviluppo Materiali (PASTIS-CNRSM), Strada Statale 7 Appia Km. 712, I-72100 Brindisi, ITALY; telephone +39 831 5071; telefax +39 831 507 240; e-mail tapfer@cnrsm.it. Key words: multilayered superconductors, laser deposition, x-ray scattering, superstructure, interface roughness. 68.65+g; 74.80.Dm; 81.15.Fg; 61.10.Kw.

T. P. Devereaux and A. P. Kampf, "Electronic Raman Scattering in Nearly Antiferromagnetic Fermi Liquids." Department of Physics, George Washington University, Washington, DC 20052.

Ujjual Divakar, G. L. Bhalla, S. K. Agarwal, and A. V. Narlikar, "Low Field ac Susceptibility Studies of Gamma Irradiated Granular YBCO Superconductors: Magnetic History Effects." To be published in Physica C (in press). Contact G. L. Bhalla, Department of Physics and Astrophysics, University of Delhi, Delhi-110 007, INDIA; telefax +91 11 725 6541.

S. G. Doettinger, S. Kittelberger, R. P. Huebener, and C. C. Tsuei, "Quasiparticle Energy Relaxation in the Cuprate Superconductors." Submitted to Phys. Rev. B. Department of Applied Physics, Stanford University, Stanford, CA 94305. 74.25.Fy; 74.76.-w; 74.60.Ge.

T. B. Doyle, R. Labusch, and R. A. Doyle, "Vortex-Lattice Melting in High-Tc Superconductors." To be published in the Proc. of the 3rd European Conf. on Appl. Supercond. (EUCAS'97), Veldhoven, The Netherlands, June 30-July 3, 1997. Department of Physics, University of Natal, King George V Avenue, Durban 4001, SOUTH AFRICA; telephone +27 31 260 2775; telefax +27 31 261 6550.

T. B. Doyle, R. Labusch, R. A. Doyle, T. Tamegai, and S. Ooi, "The Shape-Effect and Vortex-Lattice Phase Transitions in a BSCCO Single Crystal." To be published in the Proc. of the 3rd European Conf. on Appl. Supercond. (EUCAS'97), Veldhoven, The Netherlands, June 30-July 3, 1997. Department of Physics, University of Natal, King George V Avenue, Durban 4001, SOUTH AFRICA; telephone +27 31 260 2775; telefax +27 31 261 6550.

I. Eremin, M. Eremin, S. Varlamov, D. Brinkmann, M. Mali, and J. Roos, "Spin Susceptibility and Pseudogap in YBa2Cu4O8: An Approach via a Charge-Density-Wave Instability." To be published in Phys. Rev. B (Vol. 56, No. 17). Department of Physics, Kazan State University, 420008 Kazan, RUSSIA; D. Brinkmann's telephone at University of Zurich +41 1 635-5751 or -5721; telefax +41 1 635-5704; e-mail brinkman@physik- rzu.unizh.ch. 74.72.-h; 71.45.Lr; 64.90.+b.

Mikael Fogelstroem, Sungkit Yip, and Juhani Kurkijaervi, "Pinhole Junctions in d-Wave Superconductors." To be published in Physica C. Contact Sungkit Yip, Department of Physics & Astronomy, Northwestern University, Evanston, IL 60208; telefax (847) 491-9982; e-mail yip@snowmass.phys.nwu.edu; preprint also available at cond- mat@xxx.lanl.gov (#9709120). Key words: superconducting junctions, unconventional pairing. 74.50.+r; 74.72.-h.

K. Fujinami, T. Ito, H. Suematsu, K. Matsuura, M. Karppinen, and H. Yamauchi, "Establishment of a Strongly Overdoped State in the HgBa2Ca2Cu3O8+d Superconductor." To be published in Phys. Rev. B. Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226, JAPAN; H. Yamauchi's telephone +81 45-924 5315; telefax +81 45-921 6953 or -924 5360; e-mail yamauchi@materia.titech.ac.jp. 74.25.Fy; 74.62.Dh; 74.72.Jt.

V. Gantmakher, "Superconductor-Insulator Transitions and Insulators with Localized Pairs." Presented at the MESO-97 Conf., Chernogolovka, RUSSIA, June, 1997. Institute of Solid State Physics, Russian Academy of Sciences, 142432 Chernogolovka, RUSSIA; e-mail gantm@issp.ac.ru; preprint also available at cond-mat@xxx.lanl.gov (#9709017).

Jochen Glaser, "Synthesis, Structure and Superconducting Properties of Bismuth Cuprates of Type 1212 and 1223." Submitted as a Ph.D. thesis (University of Tuebingen). Institut fuer Anorganische Chemie der Universitaet Tuebingen, Auf der Morgenstelle 18, D-72076 Tuebingen, GERMANY. Key words: x-ray powder diffraction, Ca-substitution for Sr and Y, post-annealing, carrier concentration. (In German)

K. E. Gray, D. G. Steel, J D. Hettinger, and M. M. Eddy, "Modeling Flux- Flow Dissipation from Randomly-Placed Strong Pinning Sites and Comparison with Ion-Irradiated Cuprate Superconductors." Submitted to Phys. Rev. B. Contact Janice Coble, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439; telefax (708) 252-9595; e-mail janice_coble@qmgate.anl.gov. 74.40.+k; 74.60.Ge; 74.50.+r.

V. P. Gusynin, V. M. Loktev, and S. G. Sharapov, "Pseudogap Phase Formation in the Crossover from Bose-Einstein Condensation to BCS Superconductivity." Submitted to Phys. Rev. B. Bogolyubov Institute for Theoretical Physics, 252143 Kiev, UKRAINE; S. G. Sharapov's e-mail sharapov@scientia.up.ac.za; preprint also available at cond- mat@xxx.lanl.gov (#9709034). 74.72.-h; 74.20.Fg; 74.20.Mn; 64.60.Cn.

S. Haffner, R. Neudert, M. Kielwein, M. Knupfer, M. S. Golden, G. Krabbes, J. Fink, H. Rosner, R. Hayn, H. Eisaki, S. Uchida, Z. Hu, M. Domke, and G. Kaindl, "The Unoccupied Electronic Structure of Sr2CuO2Cl2 and Ba2Cu3O4Cl2: Experiment and Theory." Submitted to Phys. Rev. B. Institut fuer Festkoerper- und Werkstofforschung Dresden, Postfach 270016, D-01171 Dresden, GERMANY. 74.72.Jt; 78.70.Dm; 71.27.+a.

G. Hampel, B. Batlogg, K. Krishana, N. P. Ong, W. Prusseit, H. Kinder, and A. C. Anderson, "Third-Order Nonlinear Microwave Response of YBCO Thin Films and Single Crystals." Lucent Technologies, Bell Laboratories, Murray Hill, NJ 07974.

G. C. Han, C. K. Ong, S. Y. Xu, and H. P. Li, "A Scaling Law for ac Susceptibility of an YBa2Cu3O7-d Film in a Perpendicular ac Field." To be published in Appl. Phys. Lett. (in press). Department of Physics, National University of Singapore, 10 Kent Ridge Crescent, 119260, SINGAPORE; telephone +65 874 2816; telefax +65 777 6126; e-mail phyhangc@leonis.nus.sg.

K. Haese, B. Holzapfel, and L. Schultz, "Superconducting YNi2B2C Thin Films Prepared by Pulsed Laser Deposition." To be published in Physica C (in press). Institut fuer Festkoerper- und Werkstofforschung Dresden e.V., IMW/26, Postfach 270016, D-01171 Dresden, GERMANY; telephone +49 351 4659 478; telefax +49 351 4659 541; e-mail haese@ifw-dresden.de. Key words: thin films, YNi2B2C, electrical resistivity, critical current density, upper-critical-field H_[c2], magnetization.

J. Hauck, K. Bickmann, and K. Mika, "Pseudobinary Phase Diagrams of RBa2Cu3Ox, R = La, Ce, Pr, Nd and Y." To be published in Supercond. Sci. & Technol. Solid State Physics, Research Centre Juelich, D-52425 Juelich, GERMANY.

Zhanglian Hong, Minquan Wang, Guohong Xiong, and Xianping Fan, "Effect of Sr and Ca Solid-Solution Behavior on Superconductive Properties as Determined by Microstructure Analysis." To be published in Physica C (in press). Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, PEOPLE'S REPUBLIC OF CHINA; telephone +86 571 7990893; telefax +86 571 7951358; e-mail msezlh@ema.zju.edu.cn. Key words: XPS, substitution effects, synthesis, hole concentration.

M. Houssa and M. Ausloos, "What Does the Field Dependence of the Thermal Conductivity of the Heavy Fermion Superconductor UPt3 Tell Us About the Symmetry of the Order Parameter?" To be published in Phys. Rev. Lett. Interuniversity Micro-Electronics Centre, Kapeldreef 75, B-3001 Leuven, BELGIUM; telephone +32 1628 1404; telefax +32 1628 1315; e-mail houssa@imec.be; Web site http://www.imec.be. 74.70.Tx; 74.25.Fy; 74.60.Ec.

M. Iavarone, Y. De Wilde, P. Guptasarma, D. G. Hinks, G. W. Crabtree, and P. C. Canfield, "STM Investigation of the Superconducting State of BSCCO 2212 and Borocarbide Materials." 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. Contact Janice Coble, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439; telefax (708) 252-9595; e-mail janice_coble@qmgate.anl.gov.

L. Jansen and R. Block, "Effect of Pressure and of Doping on Superconductivity in the Double-Mercury-Layer Cuprate Hg2 (N=2): A Quantitative Analysis Based on Indirect-Exchange Pairing." To be published in Physica A. Theoretische Physik, ETH-Hoenggerberg, CH-8093 Zurich, SWITZERLAND; telefax: +41 1 633 1115; e-mail jansen@itp.phys.ethz.ch.

T. H. Johansen, M. R. Koblischka, H. Bratsberg, and P. O. Hetland, "Critical-State Model with a Secondary High-Field Peak in Jc(B)." To be published in Phys. Rev. B (Vol. 56, No. 17). Department of Physics, University of Oslo, P.O. Box 1048, Blindern, N-0316 Oslo 3, NORWAY. 74.25.Ha; 74.60.Ge; 74.60.Jg.

A. R. Jurelo, J. V. Kunzler, J. Schaf, P. Pureur, and J. Rosenblatt, "Fluctuation Conductivity and Microscopic Granularity in Bi-Based High Temperature Superconductors." To be published in Phys. Rev. B. Contact P. Pureur, Instituto de Fisica, Universidade Federal do Rio Grande do Sul, P.O. Box 15051, 91501-970 Porto Alegre, BRAZIL; telephone +55 51 3166458; telefax +55 51 3191762; e-mail ppureur@if.ufrgs.br. Key words: granular superconductors, electrical conductivity, fluctuation effects. 74.40.+k; 74.72.Hs; 74.80.Bj.

E. Kaldis, "Lattice Instabilities, Structural Anomalies and Phase Transitions in Y1-yCayBa2Cu3Ox Phases." To be published in Workshop on High-Tc Superconductivity 1996: Ten Years After the Discovery, NATO ASI Series (Kluwer Academic Publishers, 1997). Laboratorium fuer Festkoerperphysik, Eidgenoessische Technische Hochschule-Technopark, PFA-G 17, Technoparkstr. 1, CH-8005 Zurich, SWITZERLAND; telephone +41 1 633 2251; telefax +41 1 633 1126; e-mail kaldis@solid.phys.ethz.ch.

C. Kendziora, S. B. Qadri, and E. Skelton, "Pb Substitution in the Bi2Sr2CaCu2O8+d High Tc Superconductor: Cation Overdoping." To be published in Phys. Rev. B. Naval Research Laboratory, Washington DC 20375.

Shakeel Khan, Mohd. Ikram, Arti Singh, and R. J. Singh, "EPR Study of Deoxygenated La2CuO4." To be published in Physica C (in press). Contact R. J. Singh, Department of Physics, Aligarh Muslim University, Aligarh 202002, INDIA; telephone +91 57 1401001. Key words: high-Tc superconductors, Cu-O planes, ESR. 74.72.-h; 76.30.-v; 75.10.Dg.

Chan-Joong Kim, Ki-Baik Kim, Il-Hyun Kuk, Gye-Won Hong, Yi-Sung Lee, and Hyun-Soon Park, "Microstructure Change During Oxygen Annealing and the Effect on the Levitation Force of Melt Textured Y-Ba-Cu-O Superconductors." To be published in Supercond. Sci. & Technol. 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.

Chan-Joong Kim, Il-Hyun Kuk, Gye-Won Hong, Tae-Hyun Sung, Sang-Chul Han, and Jin Joong Kim, "CeO2 as a Growth Inhibitor of Y2BaCuO5 in a Ba3Cu5Ox Liquid Phase." To be published in J. Mater. Lett. 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.

Susan P. Klein, Rui-Ping Wang, Arthur W. Sleight, and William W. Warren, Jr., "NMR and NQR Study of Atomic Motion Below 500 K in YBa2Cu3O7." To be published in Phys. Rev. B. Contact William W. Warren, Jr., Department of Physics, Weniger Hall 301, Oregon State University, Corvallis, OR 97331-6507; e-mail wwarren@physics.orst.edu.

J. Koetzler and M. Kaufmann, "Two-Dimensional Fluctuations Close to the Zero-Field Transition of Bi2Sr2CaCu2O8." To be published in Phys. Rev. B. Institut fuer Angewandte Physik, Universitaet Hamburg, Jungiusstrasse 11, D-20355 Hamburg, GERMANY; e-mail kotzler@physnet.uni- hamburg.de; preprint also available at cond-mat@xxx.lanl.gov (#9709071). 74.40.+k; 74.25.Fy; 74.72.Hs.

V. M. Krasnov, N. Mros, A. Yurgens, D. Winkler, and T. Claeson, "Fluxon Modes in Stacked HTSC Intrinsic Josephson Junctions." Submitted to the Proc. of the 6th Int. Supercond. Electronics Conf. (ISEC'97), Berlin, Germany, June 26-28, 1997. Department of Physics, Chalmers University of Technology, S-41296 Goeteborg, SWEDEN; e-mail krasnov@fy.chalmers.se.

V. M. Krasnov and D. Winkler, "Static and Dynamic Properties of Stacked Josephson Junctions: Analytic Solution." To be published in Phys. Rev. B. Department of Physics, Chalmers University of Technology, S-41296 Goeteborg, SWEDEN; e-mail krasnov@fy.chalmers.se. 74.80.Dm; 74.50.+r.

L. Krusin-Elbaum, D. Lopez, J. R. Thompson, R. Wheeler, J. Ullmann, C. W. Chu, and Q. M. Lin, "Fission of Mercury: Towards High-Field Performance of Cuprate Superconductors Above 100 K." To be published in Nature. IBM Thomas J. Watson Research Center, P.O. Box 218, Yorktown Heights, NY 10598.

C. Kuebert and P. J. Hirschfeld, "Vortex Contribution to Specific Heat of Dirty d-Wave Superconductors: Breakdown of Scaling." Department of Physics, Williamson Hall, University of Florida, Gainesville, FL 32611; telephone (352) 392-0487; telefax (352) 392-0524; e-mail chris@phys.ufl.edu; preprint also available at cond-mat@xxx.lanl.gov (#9708221). 74.25.Fy; 74.72.-h; 74.25.Jb.

Y. Kubozono, T. Nakai, T. Urakawa, Y. Yoshida, H. Maeda, T. Ishii, S. Kashino, Y. Iwasa, M. Kawaguchi, T. Mitani, and S. Emura, "XAFS Study of bcc Fullerene Compounds: Rb6C60,Ba6C60 and K3Ba3C60." To be published in Physica C (in press). Faculty of Science, Department of Chemistry, Okayama University, 3-1-1, Tsushima, Okayama 700, JAPAN; telefax +81 86 251 7850; e-mail kubozono@cc.okayama-u.ac.jp.

M. Lelovic, S. Mench, T. Deis, N. G. Eror, U. Balachandran, V. Selvamanickam, and P. Haldar, "ac Magnetic Field Losses in BSCCO-2223 Superconducting Tapes." 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 Materials Science, University of Pittsburgh, Pittsburgh, PA 15261; preprints 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.

Ning Li, David Noever, Tony Robertson, Ron Koczor, and Whitt Brantley, "Static Test for a Gravitational Force Coupled to Type II YBCO Superconductors." To be published in Physica C (in press). Contact David Noever, University of Alabama in Huntsville, Huntsville, AL 35804; telephone (205) 544-7783; telefax (205) 544-2102.

E. Maiser, W. Mexner, R. Schaefer, T. Schreiner, P. Adelmann, G. Czjzek, J. L. Peng, and R. L. Greene, "Peculiar Low-Temperature Properties of Metallic Nd2-xCexCuO4 Caused by Interactions Between Nd Moments and Conduction Electrons." To be published in Phys. Rev. B. Forschungszentrum Karlsruhe, Institut fuer Nukleare Festkoerperphysik, P.O. Box 3640, D-76021 Karlsruhe, GERMANY. 74.72.Jt; 72.15.Qm; 72.15.Gd; 75.40.Cx.

J. McDonald and John R. Clem, "Microwave Response and Surface Impedance of Weak Links." Contact John R. Clem, Ames Laboratory-USDOE and Department of Physics and Astronomy, Iowa State University, Ames, IA 50011-3020; telephone (515) 294-4223; telefax (515) 294-0689; e-mail clem@ameslab.gov.

A. S. Moskvin and A. S. Ovchinnikov, "Polar Jahn-Teller Centers and Magnetic Neutron Scattering Cross-Section in Copper Oxides." Department of Physics, Ural State University, 620083, Ekaterinburg, RUSSIA; telefax +7 3432 615 978; e-mail alexandr.moskvin@usu.ru; preprint also available at cond-mat@xxx.lanl.gov (#9709033). Key words: copper oxides, magnetic form factor. 75.40.Gb; 74.25.Ha.

R. Movshovich, M. A. Hubbard, M. B. Salamon, A. V. Balatsky, R. Yoshizaki, and J. L. Sarrao, "Low-Temperature Phase Transition in Bi2Sr2Ca(NixCu1-x)2O8: Evidence for Unconventional Superconductivity." Preprint #LA/UR-97-1491. Los Alamos National Laboratory, MS K764, Los Alamos, NM 87545; telephone (505) 667-7499; telefax (505) 665-7652; e- mail roman@lanl.gov; preprint also available at cond-mat@xxx.lanl.gov (#9709061). 74.72.Bk; 74.25.Fy; 74.62.Fj.

I. P. Nevirkovets, "Slow Electromagnetic Waves in Asymmetric SISIS' Junctions." To be published in Physica C (in press). Institute for Metal Physics, National Academy of Sciences of the Ukraine, Vernadsky Blvd. 36, 252180 Kyiv-142, URKAINE; telephone +380 44 444 3432; telefax +380 44 444 3432; e-mail ipn@d24imp.kiev.ua. Key words: stacked junctions, Josephson effect, proximity effect, electromagnetic waves, Swihart velocity. 74.50.+r; 74.80.Dm.

S. Nonaka and K. Osamura, "Influence of Calcining Temperature on Critical Current Density of Ag/Bi2223 Tapes." To be published in Physica C (in press). Contact K. Osamura, Department of Materials Science and Engineering, Kyoto University, Sakyo-ku, Kyoto 606-01, JAPAN; telephone +81 75 7535434; telefax +81 75 7534861; e-mail osamura@hightc.mtl.kyoto-u.ac.jp.

C. Panagopoulos, J. R. Cooper, and T. Xiang, "Systemic Behavior of the In-Plane Penetration Depth in d-Wave Cuprates." Submitted to Phys. Rev. B. Interdisciplinary Research Centre in Superconductivity, University of Cambridge, Madingley Road, Cambridge CB3 0HE, UNITED KINGDOM; telephone +44 1223 337-046 or -076; telefax +44 1223 337-074; e-mail cp200@hermes.cam.ac.uk. 74.25.Nf; 74.72.Gr; 74.72.Bk.

C.-H. Pao and H.-B. Schuettler, "Superconducting Instability in the Holstein-Hubbard Model: A Numerical Renormalization Group Study." Preprint #ccuth97-08. Department of Physics, National Chung Cheng University, 160 San-Hsing, Min-Hsiung, Chia-Yi, Taiwan, REPUBLIC OF CHINA; telephone +886 5 2428163 or -2720411, ext. 6259; telefax +886 5 2720587; e-mail pao@phy.ccu.edu.tw; preprint also available at cond- mat@xxx.lanl.gov (#9708216).

M. Paranthaman, S. S. Shoup, D. B. Beach, R. K. Williams, and E. D. Specht, "Epitaxial Growth of BaZrO3 Films on Single Crystal Oxide Substrates Using Sol-Gel Alkoxide Precursors." To be published in Mater. Res. Bull. Chemical and Analytical Sciences Division, Bldg. 4500 South, MS-6100, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6100; telephone (423) 574-5045; telefax (423) 574-4939; e-mail p11@ornl.gov. Key words: inorganic compounds, thin films, epitaxial growth, sol-gel chemistry, x-ray diffraction.

W. Paul, M. Lakner, J. Rhyner, P. Unternaehrer, Th. Baumann, M. Chen, L. Widenhorn, and A. Guerig, "Test of 1.2 MVA High-Tc Superconducting Fault Current Limiter." Presented at the 3rd European Conf. on Appl. Supercond. (EUCAS'97), Veldhoven, The Netherlands, June 30-July 3, 1997. ABB Corporate Research, Baden-Daettwil CH-5405, SWITZERLAND; telephone +41 56 4868146; telefax +41 56 4867314; e-mail willi.paul@chcrc.abb.ch.

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

David Pines, "Understanding High Temperature Superconductivity: Progress and Prospects." Center for Nonlinear Studies, Los Alamos National Laborary, Los Alamos, NM 87545 or Department of Physics, Loomis Laboratory of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, IL 61801-3080; telephone (217) 333-0115; telefax (217) 244-7559; e-mail d-pines@uiuc.edu.

S. J. Powell, O. T. Inal, and U. Balachandran, "Effect of Shock Loading on Critical Current Density of BSCCO/Ag Tapes." To be published in the Proc. of the 1997 Annual Meeting of the Amer. Ceram. Soc., Cincinnati, Ohio, May 4-7, 1997. New Mexico Institute of Mining and Technology, Socorro, NM 87801; 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.

C. Prouteau, F. Warmont, Ch. Goupil, J. F. Hamet, and Ch. Simon, "Angular Dependence of the Resistivity of YBa2Cu3O7 Superconducting a- Axis Oriented Thin Films." To be published in Physica C (in press). Contact Ch. Simon, Laboratoire CRISMAT, UMR CNRS 6508, ISMRA-Universite de Caen, F-14050 Caen Cedex, FRANCE; telefax +33 2 3195 1600; e-mail simon@crismat.ismra.fr. Key words: superconducting, a-axis films, YBaCuO, resistivity.

C. Rasmussen and S. K. Olson, "ac-Loss Measurements on HTSC Cable Conductor with Transposed BSCCO Tapes." Presented at the 3rd European Conf. on Appl. Supercond. (EUCAS'97), Veldhoven, The Netherlands, June 30-July 3, 1997. Department of Electric Power Engineering, Technical University of Denmark, DTU-Building 325, DK-2800 Lyngby, DENMARK; telephone +45 45 88 1633; telefax +45 45 88 6111.

C. Rial, E. Moran, M. A. Alario-Franco, U. Amador, and N. H. Andersen, "Structure and Superconductivity of Room Temperature Chemically Oxidized La2-xNdxCuO4+y (0<=x<=0.5)." To be published in Physica C (in press). Contact U. Amador, Department of Quimica Inorganica y Materiales, Facultad de Ciencias Experimentales y Tecnicas, Universidad San Pablo- CEU, Urb. Monteprincipe, E-28668 Boadilla del Monte, Madrid, SPAIN; telephone +34 1 352 0144, ext. 229; telefax +34 1 351 0475; e-mail ulises@ucmrx3.quim.ucm.es or uamador@hendrix.ceu.es. Key words: La2- xNdxCuO4+y, La2CuO4, superconductor, neutron diffraction, oxygen stoichiometry.

Jose Riera and Elbio Dagotto, "Revisiting Two Holes in a Locally Antiferromagnetic Background: The Role of Retardation and Coulomb Repulsion Effects." Instituto de Fisica Rosario y Departamento de Fisica, Avenida Pellegrini 250, 2000 Rosario, ARGENTINA; preprint also available at cond-mat@xxx.lanl.gov (#9708185). 74.20.-z; 74.20.Mn; 74.25.Dw.

Sascha Sadewasser, Yong Wang, James S. Schilling, Hong Zheng, Arvydas P. Paulikas, and Boyd W. Veal, "Pressure-Dependent Oxygen Ordering in Strongly Underdoped YBa2Cu3O7-y." To be published in Phys. Rev. B. Department of Physics, Washington University, C.B. 1105, One Brookings Drive, St. Louis, MO 63130.

Kazuhiro Sano and Yoshiaki Ono, "Superconductivity of the One- Dimensional d-p Model with p-p Transfer." Department of Physics Engineering, Mie University, Tsu, Mie 514, JAPAN; e-mail sano@phen.mie- u.ac.jp; preprint also available at cond-mat@xxx.lanl.gov (#9708230). 71.10.Fd; 71.10.Hf; 74.20.Mn.

Nick Savvides and Karl-Heinz Muller, "ac Susceptibility and ac Loss in Bi-2223/Ag Superconducting Tapes." To be published in Adv. Cryogenics Eng.: Proc. of the Int. Cryogenic Eng. Conf. and the Int. Cryogenic Mater. Conf. (Joint CEC/ICMC 1997 Conf.), Portland, Oreg., July 27-Aug. 1, 1997. CSIRO Telecommunications and Industrial Physics, Bradfield Road, West Lindfield, P.O. Box 218, Lindfield NSW 2070, AUSTRALIA; telephone +61 2 9413 7359; telefax +61 2 9413 7631; e-mail nick.savvides@tip.csiro.au.

N. Savvides, A. Thorley, and D. Reilly, "Critical Current and Strain Tolerance of Bi-2223/Ag Multifilament Tapes." To be published in Adv. Cryogenics Eng.: Proc. of the Int. Cryogenic Eng. Conf. and the Int. Cryogenic Mater. Conf. (Joint CEC/ICMC 1997 Conf.), Portland, Oreg., July 27-Aug. 1, 1997. CSIRO Telecommunications and Industrial Physics, Bradfield Road, West Lindfield, P.O. Box 218, Lindfield NSW 2070, AUSTRALIA; telephone +61 2 9413 7359; telefax +61 2 9413 7631; e-mail nick.savvides@tip.csiro.au.

Stefan Scheidl and Valerii M. Vinokur, "Driven Dynamics of Periodic Elastic Media in Disorder." Submitted to Phys. Rev. E. Institut fuer Theoretische Physik, Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln, GERMANY; 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.

Bruce A. Scott, John R. Kirtley, David Walker, Bai-Hao Chen, and Yanhui Wang, "Application of Scanning SQUID Petrology to High Pressure Materials Science." To be published in Nature. Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964.

M. V. Simkin, "Domain Walls Motion and Resistivity in a Fully-Frustrated Josephson Array." Department of Physics, Brown University, Providence, RI 02912-1843; e-mail simkin@barus.physics.brown.edu.

U. Staub, L. Soderholm, S. Skanthakumar, P. Pattison, and K. Conder, "Structural Disorder in the Pb2Sr2Y1-xCaxCu3O8+d Cuprates." Swiss Light Source Project, Paul Scherrer Institute, CH-5232 Villigen PSI, SWITZERLAND; telephone +41 56 310-4494 or -2111; telefax +41 56 310- 3151; e-mail urs.staub@psi.ch. 74.72.Jt; 61.50.Ks; 61.10.-i.

C. Sulkowski, T. Plackowski, and W. Sadowski, "Thermopower Anisotropy of Underdoped and Overdoped RBa2Cu3O7-8 Single Crystals." Submitted to Phys. Rev. B. Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 937, 50-950 Wroclaw 2, POLAND; T. Plackowski's telephone +48 71 3435021, ext. 278; telefax +48 71 441029; e-mail plackow@highscreen.int.pan.wroc.pl. 74.72.Bk; 74.25.Fy.

Marc Thomas Thompson, "High Temperature Superconducting Magnetic Suspension for Maglev." Submitted as a Ph.D. thesis (Massachusetts Institute of Technology). 19 Commonwealth Road, Watertown, MA 02172; telephone (617) 923-1392; e-mail marctt@mit.edu.

D. J. Thouless, Ping Ao, Qian Niu, M. R. Geller, and C. Wexler, "Quantized Vortices in Superfluids and Superconductors." University of Washington, Seattle, WA 98195; e-mail thouless@phys.washington.edu.

Z. Tomkowicz, P. Lunkenheimer, G. Knebel, M. Balanda, A. W. Pacyna, and A. J. Zaleski, "Metal-Insulator Transition in the R1-xPrxBa2Cu3O7-d System (R=Ho,Y)." Submitted to Phys. Rev. B. Institue of Physics, Jagellonian University, Reymonta 4, 30-059 Krakow, POLAND; e-mail uftomkow@if.uj.edu.pl.

Tetsuo Tsuchiya and Kazuo Fueki, "Chemical Thermodynamics of the Hg1212 Phase." To be published in Physica C (in press). Department of Industrial Chemistry, Faculty of Science and Technology, Science University of Tokyo, 2641 Yamazaki, Noda-shi, Chiba 278, JAPAN; telefax +81 471 23 9890; e-mail a7295703@mail.rs.noda.sut.ac.jp. Key words: Hg1212 superconductor, oxygen non-stoichiometry, thermodynamical stability, Hg and Cu valence states.

H. Understrup and P. Vase, "Factors Affecting the Accuracy of Transport ac Loss Measurements on HTSC Tapes." Presented at the 3rd European Conf. on Appl. Supercond. (EUCAS'97), Veldhoven, The Netherlands, June 30-July 3, 1997. Department of Electric Power Engineering, Technical University of Denmark, DTU-Building 325, DK-2800 Lyngby, DENMARK; telephone +45 45-88 1633 or -25 3519; telefax +45 45-88 6111; e-mail hu@eltek.dtu.dk.

Arturas Vailionis, "Microstructural Properties of Some Oxide Thin Films Studied by X-ray Diffraction and Extended X-ray Absorption Fine Structure." Submitted as a Ph.D. thesis (Royal Institute of Technology). Materials Physics, Department of Physics, Royal Institute of Technology, S-100 44 Stockholm, SWEDEN; telephone +46 8 790 6058; telefax +46 8 24 91 31; e-mail arturas@matphys.kth.se. Key words: oxide thin films, high-temperature superconductor, heteroepitaxy, molecular-beam epitaxy, x-ray diffraction, extended x-ray absorption fine structure, cation disorder, stacking faults, misfit strain, CuO2 planes.

I. Van Driessche, R. Carolissen, G. Vanhoyland, and S. Hoste, "Development of High Power Magnetron Sputtering Targets Prepared by Flame Spraying." To be published in the Proc. of the 3rd European Conf. on Appl. Supercond. (EUCAS'97), Veldhoven, The Netherlands, June 30-July 3, 1997. Department of Inorganic and Physical Chemistry, University of Gent, Krijgslaan 281, B-9000 Gent, BELGIUM; telephone +32 9 264-4440 or -4421; telefax +32 9 264-4983; e-mail isabel.vandriessche@rug.ac.be.

G. E. Volovik, "On Edge States in Superconductors with Time Inversion Symmetry Breaking." Low Temperature Laboratory, Helsinki University of Technology, P.O. Box 2200, FIN-02015 HUT, FINLAND; e-mail volovik@boojum.hut.fi; preprint also available at cond-mat@xxx.lanl.gov (#9709084).

Balam A. Willemsen, T. Dahm, and D. J. Scalapino, "Microwave Intermodulation in Thin Film High-Tc Superconducting Miocrostrip Hairpin Resonators: Experiment and Theory." Submitted to Appl. Phys. Lett. Superconductor Technologies, 460 Ward Dr., Suite F, Santa Barbara, CA 93111-2310; telephone (805) 683-7646; telefax (805) 683-8527; e-mail balamw@suptech.com; Web site http://www.suptech.com. 85.25.Na; 85.25.Am; 84.40.Az; 74.76.Bz.

Masashi Yamashiro, Yukio Tanaka, and Satoshi Kashiwaya, "Tunneling Conductance of Normal Metal/Insulator/Sr2RuO4 Junction." Graduate School of Science and Technololgy and Department of Physics, Niigata University, Ikarashi, Niigata 950-21, JAPAN; e-mail masashi@bussei.sc.niigata-u.ac.jp; preprint also available at cond- mat@xxx.lanl.gov (#9709097).

Masashi Yamashiro, Yukio Tanaka, Yasunari Tanuma, and Satoshi Kashiwaya, "Theory of Tunneling Spectroscopy for Normal Metal/Insulator/Triplet Superconductor Junctions." Graduate School of Science and Technology and Department of Physics, Niigata University, Ikarashi, Niigata 950-21, JAPAN; e-mail masashi@bussei.sc.niigata-u.ac.jp; preprint also available at cond-mat@xxx.lanl.gov (#9709096). 74.50.+r; 74.80.Fp; 74.70.Tx.

J. Yao, P. B. Merrill, S. S. Perry, D. Marton, and J. W. Rabalais, "Thermal Stimulation of the Surface Termination of LaAIO3{100}." Preprint #97:095; submitted to J. Chem. Phys. Texas Center for Superconductivity, University of Houston, Houston, TX 77204-5932; telephone (713) 743-8200; telefax (713) 743-8201; e-mail preprints@www.tcs.uh.edu.

S. Yunoki, J. Hu, A. L. Malvezzi, A. Moreo, N. Furukawa, and E. Dagotto, "Phase Separation in Electronic Models for Manganites." National High Magnetic Field Lab and Department of Physics, Florida State University, Tallahassee, FL 32306; preprint also available at cond-mat@xxx.lanl.gov (#9706014). 71.10.-w; 75.10.-b; 75.30.Kz.

A. V. Zaitsev and D. V. Averin, "Theory of ac Josephson Effect in Superconducting Constrictions." Institute of Radioengineering and Electronics, Russian Academy of Sciences, 107903 Moscow, RUSSIA; e-mail zaitsev@hitech.cplire.ru; preprint also available at cond- mat@xxx.lanl.gov (#9708190).

*G. Z. Zhang, M. S. Wong, and S. S. Wang, "Strain Tolerance of Superconducting Properties and Cryogenic Mechanical Behavior of MgO- Whisker Reinforced Bulk HTS BPSCCO Composite." Preprint #97:093; 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. *New citation.

X.-M. Zhu and P. Ao, "Vortex Dynamics, Resistivity Formula, and Fluctuation-Dissipation Theorems." Department of Experimental Physics, Umea University, S-901 87 Umea, SWEDEN.

Y. T. Zhu, P. S. Baldonado, E. J. Peterson, Y. S. Park, A. Manthiram, D. P. Butt, D. E. Peterson, and F. M. Mueller, "Variation of Oxygen Content and Crystal Chemistry of YBa4Cu3O8.5+d." Submitted to Physica C. MS G755, Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545; telephone (505) 667-4029; telefax (505) 667-2264; e-mail yzhu@lanl.gov.

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

Dec. 15 - 17, 1997: Conference on Superconductivity, Hyderabad, India. Suggested topics: flux quantization, Aharanov-Bohm effect, flux creep, flux lattices, magnetization (including paramagnetic Meissner effect), microwave absorption, ESR/NMR/Mossbauer effects and positrons in superconductors, Hubbard model, Berry's phase, theories of superconductivity, Bose condensation and superfluidity, synthesis, properties, and applications of superconductors. Invited, oral, and poster papers. Selected papers to be published in proceedings. Abstract deadline, October 10, 1997. Contact K. N. Shrivastava, School of Physics, University of Hyderabad, P.O. Central University, Hyderabad 500046, India; telephone +91 40 301-0227 or -0811; telefax +91 40 301- 0145 or -0120; e-mail knssp@uohyd.ernet.in.

*Jan. 6 - 9, 1998: 7th Joint MMM-Intermag Conference, San Francisco, Calif. Conference will include all basic and applied science technology related to magnetism. The technical subject categories are: cooperative phenomena and fundamental magnetic properties, transport properties, computational magnetics and imaging, soft magnetic materials and applications, hard magnetic materials and applications, other materials, artificially structured materials, magnetic recording, and interdisciplinary topics and applications. Invited talks, oral presentations, and poster sessions. Exhibition of services, equipment, and materials. Proceedings to be published in special issues of J. Appl. Phys. and IEEE Trans. on Mag. For further information, contact Diane Suiters or Amy Landsbaum, Conference Coordinators, 655-15th Street N.W., Suite 300, Washington, DC 20005; telephone (202) 639-5088; telefax (202) 347-6109; e-mail magnetism@courtesy.assoc.com. Technical questions regarding abstracts should be directed to one of the Program Chairs: Alison Chaiken, Mailstop L-350, Lawrence Livermore Laboratory, Livermore, CA 94550, telephone (510) 422-7129, telefax (510) 422-6892, e-mail chaiken@llnl.gov; or Toasz Jagielinski, Eastman Kodak Company, 3985 Sorrento Valley Boulevard, San Diego, CA 92121, telephone (619) 535-6908, telefax (619) 535-6990, e-mail tmj@kodaksdl.com.

*Feb. 2 - 4, 1998: International Symposium on Processing and Critical Current of HTS, Wagga Wagga, New South Wales, Australia. The main topics of the symposium are: single-crystal growth; powder synthesis and novel processing; microstructure and properties; flux pinning and dynamics; two-dimensional behavior; transport, magnetic, and mechanical properties; processing for the development of flux pinning centers; fabrication of wires, tapes, magnets, and bulk materials; and applications and future trends. Papers to be published in a special issue of Superconductor Sci. and Technol. Abstract deadline, October 15, 1997. For information, contact Pavel N. Mikheenko, Centre for Superconducting & Electronic Materials, University of Wollongong, Northfields Avenue, Wollongong, NSW 2500, Australia; telephone +61 42 215726; telefax +61 42 215731.

*Feb. 19 - 24, 1998: First International Conference on New Theories, Discoveries, and Applications of Superconductors and Related Materials (New3SC-1), Baton Rouge, La. Call for papers. Purpose of conference is to attempt to determine if "a radical change is needed in the fundamental approach to superconductivity, or if the conventional approaches are likely to bear fruit soon." Conference will focus on new ideas and measurements, concepts, and models of the mechanism and origin of high-temperature superconductivity. Discussion time will be provided throughout the conference. Subjects include superconductors, giant magnetoresistance, and ferroelectric materials. Abstract deadline, December 15, 1997; early-bird registration deadline, October 15, 1997. For further information, contact J. D. Fan, Chairman New3SC, P.O. Box 9767, Baton Rouge, LA 70813-9767; telephone (504) 771-3926; telefax (504) 771-3926; e-mail new3sc@grant.phys.subr.edu; Web site http://www.phys.subr.edu/conference/new3sc.htm.

Sept. 15 - 17, 1998: Third International Symposium on Physics and Engineering of Millimeter and Submillimeter Waves (MSMW'98), Kharkov, Ukraine. Suggested topics: wave processes in finite-size solid-state structures and HTS materials, new principles of generating and receiving millimeter and submillimeter waves, radio location and communication, remote sensing, passive and active components, antennas, and other issues. Will include all aspects of millimeter-wave HTS physics, characterization of HTS materials, and HTS-based techniques. Travel grants may be available for young scientists from the FSU and other countries. Official language is English. Proceedings to be published. Abstract deadline, April 15, 1998. For further information, contact A. Kostenko, Institute of Radiophysics and Electronics, Academy of Science of Ukraine, 12 Acad. Proskura St., 310085 Kharkov, Ukraine; telefax +380 572 441105; e-mail symposium@ire.kharkov.ua. Questions related to HTS topics may be directed to N. T. Cherpak at e-mail cherpak@ire.kharkov.ua.

RESOURCES

Information

New Book: Fluctuation Phenomena in High-Temperature Superconductors, edited by Marcel Ausloos and Andrei A. Varlamov. The discussions focus on superconducting fluctuations in the vicinity of the critical transitions, superconductivity fluctuations near the percolation transition, and fluctuations of the vortex lattice at the lattice melting temperature. Publ. 1997; 456 pp.; price $217; ISBN 0-7923-4575- 4. Contact Kluwer Academic Publishers, Order Department, P.O. Box 322, 3300 AH Dordrecht, The Netherlands; telephone +31 78 6392392; telefax +31 78 6546474; e-mail services@wkap.nl.

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High-Tc Update is the high-Tc superconductivity information exchange newsletter. Please send 1) preprints, reprints, and other research reports; 2) descriptions of on-going work; 3) meeting announcements and summaries.

The information contained herein is intended for limited distribution. Readers are expected to respect the rights of the authors.

Please address all contributions and inquiries to: Dr. Sreeparna Mitra, A219 Physics, Ames Laboratory/Iowa State University, Ames, Iowa 50011-3020. Telephone: (515) 294-3877 Telefax: (515) 294-1134. E-mail: MITRA@AMESLAB.GOV or MITRA@IASTATE.EDU.

Project Director/Editor: Sreeparna Mitra Science Editor: John R. Clem High-Tc Update, Vol. 11, #19, October 1, 1997.