Spin wave resonances in antiferromagnets

TL;DR

This paper reports the observation of high wave number spin wave resonances in FeBO3, analyzes their temperature dependence, and proposes a theoretical model to explain the effects of magnon interactions and elastic distortions.

Contribution

It introduces a theoretical model explaining the observed spin wave resonances and their dependence on temperature and elastic distortions in FeBO3.

Findings

Large wave number spin wave resonances observed in FeBO3

Softening of magnon spectrum above 1/3 of Neel temperature

Excitation levels influenced by elastic distortions

Abstract

Spin wave resonances with enormously large wave numbers corresponding to wave vectors 10^5-10^6 cm^{-1} are observed in thin plates of FeBO3. The study of spin wave resonances allows one to obtain information about the spin wave spectrum. The temperature dependence of a non-uniform exchange constant is determined for FeBO3. Considerable softening of the magnon spectrum resulting from the interaction of magnons, is observed at temperatures above 1/3 of the Neel temperature. The excitation level of spin wave resonances is found to depend significantly on the inhomogeneous elastic distortions artificially created in the sample. A theoretical model to describe the observed effects is proposed.