Theoretical Study of Temperature Dependence of Spin Susceptibility in Anisotropic Itinerant Ferromagnets

TL;DR

This paper presents a theoretical framework to calculate the temperature-dependent spin susceptibility of anisotropic itinerant ferromagnets, validated through Rashba-type ferromagnets, revealing characteristic susceptibility behaviors across the Curie temperature.

Contribution

The authors develop a novel theoretical approach within the coherent potential approximation to analyze spin susceptibility over all temperatures in anisotropic itinerant ferromagnets.

Findings

Inverse transverse susceptibility is constant below T_C.

Inverse susceptibility is proportional to T - T_C above T_C.

Method successfully captures spin-orbit interaction effects.

Abstract

We developed a framework for directly calculating the spin susceptibility of anisotropic itinerant ferromagnets in the full temperature range within the coherent potential approximation in the disordered local moment picture. As a test of our formulation, we demonstrate the computation for the temperature ($T$) dependence of the spin susceptibility for Rashba-type ferromagnets with the Curie temperature $T_\mathrm{C}$. In a certain parameter, we found that the inverse transverse susceptibility $1/\chi_\perp\simeq\mathrm{const.}$ for $T<T_\mathrm{C}$ and $1/\chi_\perp\propto T-T_\mathrm{C}$ for $T>T_\mathrm{C}$, which reflects characteristics of itinerant ferromagnets including a spin-orbit interaction.