Finite temperature magnetism of FeRh compounds

TL;DR

This paper investigates the temperature-dependent magnetic phase stability of FeRh compounds using first-principles calculations and Monte Carlo simulations, revealing the interplay of exchange interactions and induced Rh magnetic moments in the metamagnetic transition.

Contribution

It introduces a combined computational approach to analyze the effects of magnetic disorder and exchange interactions on FeRh's magnetic phases at finite temperatures.

Findings

Fe-Fe exchange coupling depends on magnetic disorder.

Induced Rh magnetic moments stabilize certain phases.

Temperature influences the balance of competing magnetic factors.

Abstract

The temperature dependent stability of the magnetic phases of FeRh were investigated by means of total energy calculations with magnetic disorder treated within the uncompensated disordered local moment (uDLM) approach. In addition, Monte Carlo simulations based on the extended Heisenberg model have been performed, using exchange coupling parameters obtained rom first principles. The crucial role and interplay of two factors in the metamagnetic transition in FeRh has been revealed, namely the dependence of the Fe-Fe exchange coupling parameters on the temperature-governed degree of magnetic disorder in the system and the stabilizing nature of the induced magnetic moment on Rh-sites. An important observation is the temperature dependence of these two competing factors.