NMR Relaxation Rate of Impure Anisotropic Quasi-One-Dimensional Superconductors

Abstract

The effect of nonmagnetic impurities on the NMR relaxation time, T₁, of quasi-one-dimensional superconductors with anisotropic order parameters has been studied based on the previous calculation of the thermodynamic quantities. The relaxation rate, T₁⁻¹, is examined as a function of both temperature and the impurity concentration by taking account of the vertex correction for the impurity scattering. It is shown that the enhancement of T₁⁻¹ near the transition temperature exists only for a small concentration of impurity. By the increase of impurity, the value of T₁⁻¹ at absolute zero temperature increases continuously from zero and becomes equal to that of the normal state at the critical concentration.