Pinning of the Vortex System and Magnetostriction of Superconductors

Abstract

Hard type-II superconductors usually reveal a large, of the order of 10−5 or 10−4, magnetostriction in the external magnetic field of several Tesla. Such a strong magnetostriction can be well understood in the framework of the model of the pinning-induced magnetostriction. Although the assumptions of this model are easy to understand, the solution of the problem for realistic sample shapes is difficult, because the stress induced in the sample volume by the screening currents has non uniform distribution and it may also change the sample shape. The model of pinning-induced magnetostriction is insufficient to explain all magnetostriction results in superconductors. Sometimes, it is necessary to consider also other mechanisms of the magnetostriction. Magnetostriction of superconductors was analyzed theoretically and studied experimentally in a large number of both conventional and high temperature superconductors. In this paper we present a review of the most characteristic results. We also present the phenomenon of giant magnetostriction jumps, which is closely related to the phenomenon of giant flux jumps or thermomagnetic instabilities in type-II superconductors.