On the Surface Barrier in Type II Superconductors

Abstract

The surface barrier model originally proposed by Bean and Livingston is reinvestigated by taking account of the thermodynamic characteristics of a superconductor. The result shows that the first penetration of the fluxoids occurs at the very vicinity of the lower critical field H_c1 for a superconductor with spatial dimensions much larger than the penetration depth. The image force is not effective to retard the first penetration of the fluxoids. It is concluded that the surface irreversibility in the mixed state does not originate from the mechanism of the surface barrier.