The properties of YBCO superconductors prepared by a new approach: the 'powder melting process'

The authors have developed a new method, which they term the 'powder melting process' (PMP) for the preparation of high J_c YBCO superconductors. The YBCO conductors have been fabricated via a continuous melting and unidirectional solidification process using precursor powders of Y₂BaCuO₅ ((211) phase) and BaCuO as starting materials. The transport J_c values of the samples, measured by a standard continuous DC four-probe method, exceed 10800 A cm^-2 at 77 K and 1 T. A microstructural investigation indicated that the 123 grains are well oriented, and fine and dispersed 211 particles remained in the samples. YBCO conductors with various dimensions and shapes can be fabricated by the PMP method. This new approach has potential for the fabrication of oxide conductors with metal substrates, since its melting temperature is lower than that of other melting processes by about 100 degrees C.