Processing of High Current Density Yba₂cu₃o_x Superconductors

Abstract

A liquid phase processing method has been developed to fabricate oriented grained YBa₂Cu₃0_x samples with high current density. The current density in these samples, however, is sensitive to the microstructure which is controlled by processing parameters. Cooling rate through the peritectic temperature is found to be the most crucial factor in controlling the extent of grain orientation and in turn the bulk current carrying capacity. The evolution of the microstructure during the slow cooling process is studied by quench experiments at different temperatures. From microstructural analysis, the suitable temperature profile for the slow cooling process is chosen. Current density measurements across grains show a Jc in excess of 10⁴ A/cm². This implies that the weak link behavior of grain boundaries in polycrystalline superconductors can be suppressed to a considerable extent.