High current density in bulk YBa2Cu3Ox superconductor

Abstract

A liquid phase processing method for the fabrication of bulk YBa₂Cu₃O_x superconductors with large current carrying capacity has been developed. Slow cooling through the peritectic transformation (1030–980 °C) has been shown to control the microstructure of these superconductors. A cooling rate of 1 °C/h in this temperature range has yielded a microstructure with long plate type, thick grains oriented over a wide area. Current density up to 18 500 A/cm² has been obtained by continuous direct current measurements and in excess of 62 000 A/cm² with pulse current of 10 ms duration and 75 000 A/cm² using 1 ms pulse. The strong magnetic field dependence observed in sintered bulk 1‐2‐3 superconductors is also minimized to a large extent where a current density in excess of 37 000 A/cm² is obtained in a field of 6000 G.