A Magnetothermoelastic Theory of Type-II Superconductors in Mixed State

Abstract

This article presents a macroscopic theory for analysing magnetothermoelastic responses of type-II superconductors in a mixed state. The theory includes not only the vortex dynamic effect, the normal current effect, the Hall effect, the thermomagnetic effects, the thermoelastic effects and the Lorentz force effect, but also the effect of the London moment induced by the local motion of the deformable type-II superconductor in the mixed state. The Proposed theory may unify the macroscopic studies on electromagnetic, thermal and mechanical phenomena in type-II superconductors in the mixed state, and may also provide a tool to investigate various coupling phenomena among electromagnetism, heat conduction and mechanical motion involved in the type-II superconductor in the mixed state. The theory is considered to be valid within the framework of the generalized Galilean relativity at the magneto-quasistatic approximation. A linearized version of the theory is also introduced to analytically study some wave phenomena in the thermoelastic type-II superconductor in the mixed state. It is shown that the effect of the London moment can be of significance as compared with the effect of the normal Lorentz current on the magnetothermoelastic coupling behavior of the type-II superconductor in the mixed state. In particular, the theoretical result shows that there is an effect of phase shift in some waves propagating in the thermoelastic type-II superconductor in the mixed state. This effect is found to be closely related to the vortex dynamic properties of the superconductor.