Spin-waves in the collinear antiferromagnetic phase of Mn$_\bf{5}$Si$_\bf{3}$

TL;DR

This study combines neutron scattering and density functional theory to analyze spin-waves and magnetic interactions in the collinear antiferromagnetic phase of Mn$_5$Si$_3$, revealing field-dependent magnon behavior and potential Dzyaloshinskii-Moriya effects.

Contribution

It provides new insights into the magnetic exchange interactions, anisotropy, and spin excitation spectrum of Mn$_5$Si$_3$ using combined experimental and theoretical methods.

Findings

Identification of dominant magnetic exchange interactions.

Observation of different magnetic field dependencies of magnon modes.

Consideration of Dzyaloshinskii-Moriya interaction effects.

Abstract

By combining two independent approaches, inelastic neutron scattering measurements and density functional theory calculations, we study the spin-waves in the high-temperature collinear antiferromagnetic phase (AFM2) of Mn$_5$Si$_3$. We obtain its magnetic ground-state properties and electronic structure. This study allowed us to determine the dominant magnetic exchange interactions and magnetocrystalline anisotropy in the AFM2 phase of Mn$_5$Si$_3$. Moreover, the evolution of the spin excitation spectrum is investigated under the influence of an external magnetic field perpendicular to the anisotropy easy-axis. The low energy magnon modes show a different magnetic field dependence which is a direct consequence of their different precessional nature. Finally, possible effects related to the Dzyaloshinskii-Moriya interaction are also considered.