Influence of Heat Treatment on the Properties of Bi1.8Pb0.2Sr2Ca2Cu3Ox Ceramics and Ag-Sheathed Tapes

Optimization of a heat treatment temperature is applied to bare Bi1.8Pb0.2Sr2Ca2Cu3Ox ceramics as well as to Ag-sheathed tapes prepared by the powder in tube method. We discuss structural differences observed by SEM and the phase content and FWHM of rocking curves obtained by X-ray diffraction. Further, we compare the superconducting transition temperature of short samples measured by a. c. susceptibility and the critical current anisotropy measured by the four probe method. The effect of the Ag-envelope as oxygen barrier is shown comparing the differences in the width of transition temperature. The difference in the angular dependence of critical currents reflects not only the texture but also the path in which the current is flowing.