Enhancement of ferromagnetism by p-wave Cooper pairing in superconducting ferromagnets

In superconducting ferromagnets for which the Curie temperature T-m exceeds the superconducting transition temperature T-c, it was suggested that ferromagnetic spin fluctuations could lead to superconductivity with p-wave spin-triplet Cooper pairing. Using the Stoner model of itinerant ferromagnetism, we study the feedback effect of the p-wave superconductivity on the ferromagnetism. Below T-c, the ferromagnetism is enhanced by the p-wave superconductivity. At zero temperature, the critical exchange interaction value for itinerant ferromagnetism is reduced by the strength of the p-wave pairing potential, and the magnetization increases correspondingly. More important, our results suggest that once the ferromagnetism is established, T-m is unlikely to ever be below T-c. For strong and weak ferromagnetism, three and two peaks in the temperature dependence of the specific heat are, respectively, predicted, the upper peak in the latter case corresponding to a first-order transition.