The effects of crystallization on the magnetic properties and critical current in Bi$ndash$Sr$ndash$Ca$ndash$Cu$ndash$O glass$ndash$ceramics

Abstract

We report on the influence of crystallization on the dc magnetization, the ac susceptibility, and the intergranular and intragranular critical current density of Bi4Sr3Ca3Cu4Ox crystallized glass. The samples, characterized by x-ray diffraction, contained mainly a Bi2Sr2Ca1Cu2O8 superconducting phase. The transition to the superconducting state was investigated by magnetic methods: dc magnetization and ac susceptibility. All the samples exhibited diamagnetic properties below 80 K, which is in agreement with the critical temperature of the Bi2Sr2Ca1Cu2O8 phase. The superconducting volume fraction and the values of critical current were evaluated from the magnetization measurements of the samples cooled in an applied magnetic field and the measurements of magnetization hysteresis. The values of critical current for all the samples were quite small, in the range of 50–100 A cm−2 for intergranular current, depending on the amount of superconducting phase in the sample.