Fabrication of High J_c Oxide Superconductors by a Melt Process and Their Critical Current Characteristics

YBa₂Cu₃O_x powders were rapidly heated to the Y₂O₃ plus liquid region and quenched using copper hammers. The quenched plates were again heated to the Y2BaCuO5 plus liquid region and slow cooled in a thermal gradient. The process enabled uni-directional growth of the superconducting phase. Magnetization measurements revealed that magnetic properties of the melt processed samples could be understood in terms of Bean critical state model. The samples attained J_c values exceeding 10⁴ A/cm² at 77K and 1T. Ginat flux creep was not observed in such samples.