Anomalous Specific Heat of Superconducting Magnetic Alloys

The specific heat of superconductors containing small concentrations of paramagnetic impurities is calculated. It is shown that ordering of the impurity spins gives rise to a large enhancement of the specific heat and changes strongly the dependence of the electronic specific-heat discontinuity at the superconducting transition temperature on the concentration of paramagnetic impurities. It is pointed out that the impurity-spin ordering in a superconductor is affected by nonmagnetic impurities.