Processing of single-phase ceramic 123 YBaCu-oxide superconductor by hot pressing

High-quality single-phase polycrystalline samples of high-temperature superconducting 123 YBaCu-oxide have been processed by hot pressing of specially prepared charge material at elevated temperatures. The samples are orthorhombic with unit cell dimensions a = 3.824(1) A, b = 3.888(1) A, and c = 11.679(2) A. They exhibit: (1) densities up to 82 percent of the theoretical value; (2) a sharp phase transition between the normal and superconducting states at 91.6 K; (3) a reduced dependence on thermal cycling effects and on excitation currents in resistivity measurements; and (4) a reduction in surface deterioration due to water, air, and acid attack. The hot-pressed samples supported current densities at least two orders of magnitude greater than those found in cold-pressed samples measured under similar conditions.