Superconductivity at 97 K in Bi2Sr2Ca1Cu2Oy system

Samples with the nominal composition Bi2Sr2Ca1Cu2Oy were prepared by the solid state reaction method. Samples were prepared by various heat treatments and are characterized by using d.c. electrical resistivity, susceptibility and X-ray diffraction methods. A sample annealed for many hours at high temperature and quenched from 400 °C into liquid nitrogen has exhibited superconductivity at 97 K. The X-ray diffraction of this sample shows a single phase nature. The thermal expansion data was used for choosing the optimum quenching temperature (400 °C).