Fluxoid Pinning in Nonideal Type-II Superconductors. I. Force between a Fluxoid and a Lattice Defect

Abstract

A general expression of the interaction energy between fluxoids and lattice defects is obtained by perturbational calculations of the generalized Ginzburg-Landau equations, which are derived by minimizing the free energy of the mixed state including elastic terms. The present expression is the same as Labusch’s obtained only for a special type of lattice defects with a pure shear, but is shown to be applicable to any type of defects.
The interaction force between a fluxoid and a lattice defect is derived for some typical types of defects by the use of the present expression of interaction energy, and the results of previous authors are shown to be unsatisfactory, even qualitatively. The present results give the first step for the derivation of a general expression of the so-called “pinning force”, which is the final purpose of this series.