Liquid Quenched Superconductor Ba-Y-Cu-O with Tc,zero=88 K and AC Josephson Effect at 77 K

A superconducting Ba-Y-Cu-O with T c,zero=88 K was prepared by a liquid quenching method, in which the melt of nominal composition Ba2YCu3O7-δ was first quenched and then the sample was annealed at 900°C for 48 h in air. AC Josephson effect was observed at 77 K in point-contacts made of the present samples. This new method is applicable to the preparation of superconducting thin films, wires, tapes and superconduciting cavities.