Flux Line Pinning by Large Normal Particles in Type-II Superconductors

Abstract

The pinning of flux lines by large normal particles has been investigated as a function of field and temperature. The results are compared with a model for the magnetic pinning interaction at a phase boundary. The problem of the summation procedure for individual pinning interactions is discussed and it is concluded that the distortion of the flux line lattice caused by large normal particles is large enough for a simple direct summation to apply. This conclusion is supported by the experimental results. The experimental results also indicate that Anderson flux creep is not significant in this type of pinning system.