R. L. Sabatini

A Mechanism for Resistive Dissipation in Ag Sheathed Bi2Sr2CaCu2O8 and Bi2Sr2Ca2Cu3O10

Detailed measurements of the V-I curves for a number of Bi2Sr2CaCu2O8 and Bi2Sr2Ca2Cu3O10/Ag composite tapes were made at 4.2, 27, and 64-77 K as a function of applied magnetic field as well as the angle between the tape face and the direction of applied field. The results suggest that the weak vortex-pinning strength, and the amount of the weakly coupled grain boundaries and of the non-superconducting volume are the primary limiting factors for critical current densities in Bi(2212)/Ag and Bi(2223)/Ag, respectively. Furthermore, in both cases, the dissipative voltages arise from the interior of the gains.

Superconducting Properties and Structural Characterization of High Tc Oxides

A desire to provide good quality oxide superconducting specimens for research in our materials laboratory and for collaborators at the Synchrotron Light Source, High Flux Beam Reactor, and Alternating Gradient Synchrotron required us to carefully characterize our samples. Earlier, straightforward methods for preparation YBa2Cu3O7(1) superconductors were described. However, these methods are not completely defined, and samples prepared nominally according to recipe may vary in superconducting properties and with respect to the presence of non superconducting minority phases (primarily observed in x-ray diffraction work). Here we describe methods of preparation for these oxides which we utilized, and of characterization to evaluate these materials.