The effect of sample geometry on magnetic levitation force for a disk-shape YBCO superconductor

Abstract

In this investigation, we present calculations of levitation forces between a large cylindrical permanent magnet and a small disk-shape YBCO superconductor. The induced electric current inside the superconductor was assumed to be in tube-like shape with current density equal to the average critical current density of the superconducting sample (SS). The induced magnetic field distribution can thus be calculated for both outside and inside of the superconductor. By comparing with self-consistent calculations done by other researchers, the effect of self induced field on the total field distribution can be evaluated. It is found that different sample geometries have different corrections for both first critical field ( H c1) and levitation force of the SS. However, for superconductor with smaller average critical current density, the effect of sample geometry on levitation force is smaller.