THALLIUM-CALCIUM-BARIUM-COPPER OXIDE SUPERCONDUCTIVE BODY CONTAINING SILVER AND PREPARATION THEREOF

摘要

A method is disclosed for forming polycrystalline thallium system superconductors having high current carrying capacity and high magnetic field behavior. A precursor deposit is formed comprised of silver, in an amount of about 1 to 20 mole percent of metals in the deposit, and the balance oxides of calcium, barium, and copper in ratios for forming the superconductor. The precursor deposit is annealed in an oxidizing atmosphere, and in the presence of a source of thallous oxide. The source of thallous oxide is heated to a first temperature selected to incorporate thallium into the deposit in an amount of about 6 to 22 mole percent of metals in the superconductor, and the precursor deposit is heated to a second temperature to form the superconductor. Preferably, the superconductor is post-annealed in an oxidizing atmosphere at about 500 DEG to 650 DEG C to improve the current carrying capacity in the superconductor. IMAGE