Trapped magnetic field in a superconducting disk magnetized by uniform field

TL;DR

This paper models the current density and trapped magnetic field in a superconducting disk magnetized by a uniform field, highlighting how material properties and geometry influence the trapped field.

Contribution

It provides a first-principles calculation of the trapped magnetic field in superconducting disks considering superconducting parameters and flux creep effects.

Findings

Critical current density and flux creep exponent significantly affect trapped field strength.

Higher applied magnetic field does not always increase the trapped magnetic field.

Aspect ratio influences the shape of flux lines in the superconductor.

Abstract

The distribution of the current density and the profile of the trapped magnetic field of a superconducting disk magnetized by uniform field are calculated from first principles. The effect of the superconducting parameters is taken into account by assuming the voltage-current law and the material law. The sample volume, the critical current density and the flux creep exponent dominate the strength of the trapped magnetic field. The flux creep exponent determines the decay rate of the trapped magnetic field. The aspect ratio of the sample influences the shape of the trapped magnetic flux lines. We conclude that higher trapped magnetic field cannot always be obtained by increasing the applied magnetic field.