Effect of metal impregnation in the field cool magnetization of bulk superconductor

Abstract

Gd–Ba–Cu–O bulk superconductors have significant potential for various applications due to the high critical current density and the highly trapped magnetic fields. Recently we have developed a large sized bulk superconductor using Gd210, which is discovered in the microgravity experiment. We investigated the mechanical properties and the cryostability of the Gd–Ba–Cu–O bulk superconductor to determine how to improve toughness and heat conduction of the large sized bulk superconductor. We introduced a stainless ring around the circumference of the bulk to increase the fracture strength of the bulk. Also, we introduced Al wires inserted in the hole along the c-axis of the bulk, and then the sample was subjected to the impregnation by using Bi–Sn–Cd alloy. We measured the trapped magnetic fields and the repulsive forces of the samples. The trapped magnetic field distributions were 1.13–1.36T. The repulsive forces at 1mm gap between the sample bulk and the permanent magnet with the surface magnetic induction of 0.37T were about 70N at 77K. We have also measured the temperature dependence of the trapped magnetic field, and confirmed the effect of metal impregnation.