Separation and Characterization of Superconducting YBa2Cu3O7-x Powder

The superconducting YBa2Cu3O7-x powder has been sorted using the Meissner effect. Two separation methods have been employed. One is separating the powder at a constant temperature, the other is separating it over a temperature gradient. Both methods are effective for separating the high-Tc superconducting powder from the low-Tc superconducting parts. Separated powder was examined by X-ray diffraction and quantitatively analyzed by EPMA as well as by chemical analysis, and by a TEM. The higher-Tc part of YBa2Cu3O7-x powder was characterized by smaller lattice constants, higher oxygen concentration, and higher twin density. The low-Tc YBa2Cu3O7-x sample shows a low Cu/Y ratio relative to the high-Tc sample.