A New Process with the Promise of High Jc in Oxide Superconductors

We report a new process which promises high critical current density in oxide superconductors. The process consists of three stages. Firstly a YBa 2 Cu 3 O x sample is rapidly heated and quenched from the Y 2 O 3 plus liquid region. Subsequently the quenched sample is reheated to the Y 2 BaCuO 5 plus liquid region, and then slowly cooled with a temperature gradient in flowing oxygen. The process enables us to grow a superconducting phase unidirectionally and to suppress the second phase intrusion, leading to the production of well textured YBa 2 Cu 3 O x which yields a high J c value in the presence of magnetic fields. It is also found that Bean's critical state is realized in such high J c samples.