Effect of magnetic impurities on suppression of the transition temperaturein disordered superconductors

We calculate the first-order perturbative correction to the transition temp erature T-c in a superconductor with both nonmagnetic and magnetic impuriti es. We do this by first evaluating the correction to the effective potentia l Omega(Delta) and then obtain the first-order correction to the order para meter Delta by finding the minimum of Omega(Delta). setting Delta = 0 final ly enables T-c to be evaluated. T-c is now a function of both the resistanc e per square R-square, a measure of the nonmagnetic disorder, and the spin- flip scattering rate 1/tau(s), a measure of magnetic disorder. We find that the effective pair-breaking rate per magnetic impurity is virtually indepe ndent of the resistance per square of the film, in agreement with an experi ment of Chervenak and Valles. This conclusion is supported both by the pert urbative calculation, and by a nonperturbative resummation technique.