# Low-energy spin dynamics of orthoferrites AFeO$_3$ (A = Y, La, Bi)

## TL;DR

This study investigates the low-energy spin excitations in orthoferrites YFeO$_3$ and LaFeO$_3$ using inelastic neutron scattering, revealing magnon splitting and gaps explained by advanced spin-wave calculations.

## Contribution

It provides a comprehensive analysis of spin dynamics in orthoferrites, including Dzyaloshinsky-Moriya interactions and anisotropy, unifying understanding of Fe$^{3+}$-based perovskites.

## Key findings

- Magnon branch splitting observed in both compounds
- Non-zero magnon gap similar to BiFeO$_3$
- Spin wave calculations successfully explain experimental data

## Abstract

YFeO$_3$ and LaFeO$_3$ are members of the rare-earth orthoferrites family with \textit{Pbnm} space group. Using inelastic neutron scattering, the low-energy spin excitations have been measured around magnetic Brillouin zone center. Splitting of magnon branches and non-zero magnon gap is observed for both compounds, which is similar to the behavior observed in multiferroic BiFeO$_3$. Spin wave calculations which include both Dzyaloshinsky-Moriya interactions and single-ion anisotropy in the spin-Hamiltonian comprehensively accounts for all the experimentally observed features. Our results offer insight into the unifying physics underlying the Fe$^{3+}$-based perovskites as well as their distinguishing characteristics.