Effect of nonmagnetic and magnetic impurities on the specific heat jump in anisotropic superconductors

The specific-heat jump DeltaC at a critical temperature T-c in an anisotropic superconductor containing both potential and spin-flip scatterers is calculated within a weak-coupling mean-field approximation. It is shown that the presence of even a small amount of spin-flip scatterers in the sample leads to a drastic change in the dependence of DeltaC on T-c in a disordered (d+s)-wave or a strongly anisotropic s-wave superconductor. The implications for experimental tests for the presence of an s-wave admixture in the superconducting order parameter of high-T-c superconductors are discussed.