PROCESS PARAMETERS, ORIENTATION, AND FUNCTIONAL-PROPERTIES OF MELT-PROCESSED BULK Y-BA-CU-O SUPERCONDUCTORS

This study compared the microstructure, texturing, and functional prop erties (critical currents) of YBa2Cu3O7-x-based bulk pellets that were prepared by the quench-melt-growth-process (QMGP), melt-textured grow th, and conventional solid-state reaction approaches. Using two x-ray diffraction methods, theta-2 theta, and rocking curves, we found that the individual grains of two melt-processed pellets exhibited remarkab le preferred orientational alignment (best rocking curve width = 3.2 d egrees). However, the direction of the preferred orientation among the grains was random. Among the three types of bulk materials studied, t he QMGP sample was found to have the best J(c) values, approximate to 4500 A/cm(2) at 77K in a field of 2 kG, as determined from superconduc ting quantum interference device magnetic data.