High trapped fields in melt-textured YBa2Cu3O7-delta

Bulk melt textured YBCO material with single-domain grains up to 35 mm in d iameter was prepared by a modified melt-texture process. The maximum trappe d field B-0 measured in the 1 mm gap between two single-grain dish was foun d to increase from 1.2 T at 75 Ii up to 9.6 T at 46 Ii, which is the highes t trapped field achieved in non-irradiated samples. A strong exponential de crease of the trapped field with increasing temperature found in most of th e cases can be explained by flux creep within the framework of collective p inning assuming weak pinning. A weaker B-0(T) dependence and higher B-0 val ues at temperatures between 55 and 75 K were observed in newly processed YB CO material. A pronounced peak effect found in the field dependence of the critical current density suggests strong pinning in this material. For appl ications of YBCO samples in superconducting magnetic bearings, an effective method for magnetizing the superconductor is required. Results of magnetiz ing YBCO samples by applying pulsed magnetic fields will be presented.