Search

Pulsed laser deposition on various single crystl substrates was used to fabricate epitaxial (rare earth)Ba2Cu3O7 films, RE123, with RE = Y, Er and Sm. Each material's deposition was optimized for T(sub c). An increase in ionic sized of the rare-earth element was observed in increased T(sub c) in RE123 films. In addition, the vortex pinning anisotropy was affected by the rare-earth element as shown by the study of field- and angle-dependent J(sub c).

The magnetic field dependence of isothermal melt-processed Bi-2212/Ag round wires' critical current density was measured. Minimal dependence of critical current density was observed when the magnetic field direction was rotated normal to the wire axis. When the direction of the magnetic field was rotated parallel to the wire axis, critical current density at 64 K and 0.2 T rose by more than a factor of four.

A calorimeter is proposed for the measurement of meter-long high temperature superconducting power transmission cables' alternating current (AC) losses. The device is based on a temperature differential scheme and features 1 mW precision. It was designed for single, two-phase and three phase loss measurements. The calorimeter accurately measured coupling losses between phases.

The c-axis conduction characteristics of silver-clad Bi-2223 and Bi-2212 tapes were investigated. Specifically, transport, resistivity and critical current measurements were carried out under varying temperatures and magnetic fields. The measurements, which looked at the superconducting current path parallel and perpendicular to the tape plane, revealed that the critical currents flowing along and normal to the tape plane have similar field orientation and magnetic field dependences.

Ion beam assisted deposition is used to create textured yttria-stabilized-zirconia buffer layers on flexible nickel substrates prior to the preparation of high current YBa2Cu3O7-gamma thick films. This approach enables the formation of c-oriented thick films with strong in-plane textures. The films produced using this method also exhibit excellent resistance to high magnetic fields at cryogenic temperatures.

Magnetic relaxation measurements are conducted to study the zero field cooled, field cooled warming and field cooled cooling c-axis transport properties of Bi2Sr2CaCu2O8 single crystals. Bi-2212 cristals are used in the experiments which involve the application of a magnetic field along the c-axis. Results the c-axis transport properties of the crystals are strongly influenced by the flux profile.

The trend of flux pinning in the melt-powder-melt-growth (MPMG) process was examined. This involved the comparison of the magnetic hysteresis and magnetic relaxation of three MPMG samples having different nominal concentrations of 211 inclusions. A weak field dependence of critical current and an enhanced pinning strength were exhibited by the samples prepared by the MPMG process.

Silver-clad monofilament (Bi, Pb)SrCaCuO-2223 superconducting tapes manufactured by the oxide-powder-in-tube process were measured at magnetic fields from O T to 7 T and a temperature range of 7-75 K. The measurements obtained the tapes's transport critical current densities and magnetization currents at fields parallel and perpendicular to the sample's plane. These also provided information on the magnetic relaxation and flux pinning potentials.

The fabrication and characterization of silver-clad TlBa2Ca2Cu3O(8+x) (Tl-1223) films is presented. It details the procedures performed to synthesize superconductors from thalliated precursor powders. It also presents the measurements of transport and magnetization critical current densities which reveal its suitability for high-field and high-temperature applications.