Enhancement in the critical current density of Bi-2212 superconductor via Li substitution

Abstract

This study is about examining the effect of lithium substitution for the copper site of the Bi2212 superconductor on microstructural, magnetic hysteresis and critical current densities. Superconducting samples given with the nominal formula Bi2Sr2CaCu2-xLixO8+δ where x= 0, 0.05, 0.10, 0.15, and 0.20 were produced by the classical solid state reaction method due to reasons such as ease, repeatability and low cost. To determine the microstructural properties of the samples, SEM photographs at 10 kX were taken and with the increase in Li-content, an evolution from randomly platelet-shaped grains to rectangular prism-shaped grains was observed. Critical transition temperature (Tc) values of the samples increased with Li-level in Bi-2212 observed from M-T measurements. Additionally, it is revealed from M-H measurements that the area of the hysteresis curves expanded with the increase of Li-content . Accordingly, values of remanent magnetization (Mr) and critical current density (Jc) of Bi-2212 samples were found to be increase with Li-substitution for Cu-site.