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

TL;DR

This paper investigates how p-wave superconductivity enhances ferromagnetism in superconducting ferromagnets, showing that superconductivity can reinforce magnetic order and alter phase transition characteristics.

Contribution

It provides a theoretical analysis using the Stoner model to demonstrate the feedback effect of p-wave pairing on ferromagnetism, revealing that ferromagnetism is strengthened below the superconducting transition.

Findings

Ferromagnetism is enhanced by p-wave superconductivity below T_c.

The critical Stoner value for ferromagnetism decreases with p-wave pairing strength.

Multiple peaks in specific heat indicate complex phase transitions.

Abstract

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 Stoner 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 Stoner 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.