# Magnetic excitations in frustrated fcc type-III antiferromagnet MnS$_2$

## TL;DR

This study investigates magnetic excitations in MnS$_2$, revealing multiple spin wave branches caused by magnetic frustration, with experimental data supported by a Heisenberg model analysis highlighting the effects of exchange interactions and structural deformation.

## Contribution

It provides the first detailed inelastic neutron scattering analysis of spin wave dispersion in MnS$_2$, linking magnetic frustration to structural effects and exchange interactions.

## Key findings

- Multiple spin wave branches observed, indicating magnetic frustration.
- Reduced exchange interactions suppress frustration effects.
- Structural deformation influences magnetic exchange interactions.

## Abstract

Spin wave dispersion in the frustrated fcc type-III antiferromagnet MnS$_2$ has been determined by inelastic neutron scattering using a triple-axis spectrometer. Existence of multiple spin wave branches, with significant separation between high-energy and low-energy modes highlighting the intrinsic magnetic frustration effect on the fcc lattice, is explained in terms of a spin wave analysis carried out for the antiferromagnetic Heisenberg model for this $S=5/2$ system with nearest and next-nearest-neighbor exchange interactions. Comparison of the calculated dispersion with spin wave measurement also reveals small suppression of magnetic frustration resulting from reduced exchange interaction between frustrated spins, possibly arising from anisotropic deformation of the cubic structure.