Paramagnetic limiting in ferromagnetic superconductors with triplet pairing

TL;DR

This paper investigates how paramagnetic effects influence superconductivity in ferromagnetic superconductors with triplet pairing, emphasizing the role of band splitting over magnetization rotation.

Contribution

It provides a theoretical explanation for the absence of paramagnetic limitation in certain field directions, highlighting band splitting effects in itinerant ferromagnets.

Findings

Paramagnetic limitation is absent for fields perpendicular to magnetization.

Band splitting explains the lack of paramagnetic effects, not magnetization rotation.

A qualitative model describes the upper critical field temperature dependence.

Abstract

The spin susceptibility in the uranium ferromagnet superconductors is calculated. There is shown that the absence of superconductivity paramagnetic limitation for the field directions perpendicular to the direction of the spontaneous magnetization is explained by the itinerant ferromagnet band splitting rather than by a rotation of magnetization toward the external field direction. The qualitative description of the upper critical field temperature dependence is given.