Life times and chirality of spin-waves in antiferromagnetic and ferromagnetic FeRh: time depedent density functional theory perspective

TL;DR

This paper investigates spin-wave properties in FeRh's antiferromagnetic and ferromagnetic phases using time-dependent density functional theory, revealing damping mechanisms, induced Rh moments, and chirality differences across magnetic states.

Contribution

It introduces a detailed theoretical analysis of spin excitations in FeRh, highlighting phenomena beyond the Heisenberg model such as damping, induced moments, and optical magnon formation.

Findings

Landau damping of spin waves identified

Large Rh moments induced by AFM magnons

Optical magnons terminated by Stoner excitations

Abstract

The study of the spin excitations in antiferromagnetic (AFM) and ferromagnetic (FM) phases of FeRh is reported. We demonstrate that although the Fe atomic moments are well defined there is a number of important phenomena absent in the Heisenberg description: Landau damping of spin waves, large Rh moments induced by the AFM magnons, the formation of the optical magnons terminated by Stoner excitations. We relate the properties of the spin-wave damping to the features of the Stoner continuum and compare the chirality of the spin excitations in AFM, FM and paramagnetic (PM) systems.