Magnetic excitations in the geometric frustrated multiferroic CuCrO$_2$

TL;DR

This study uses neutron scattering to analyze magnetic excitations in CuCrO$_2$, revealing the importance of extended exchange interactions and interlayer coupling in understanding its magnetic structure and multiferroic behavior.

Contribution

It provides a detailed model of magnetic interactions in CuCrO$_2$, emphasizing the significance of beyond-next-nearest neighbor and interlayer exchanges.

Findings

Exchange interactions beyond next-nearest neighbor are crucial.

Interlayer exchange influences magnetic incommensurability.

Model aligns with previous diffraction experiments.

Abstract

In this paper detailed neutron scattering measurements of the magnetic excitation spectrum of CuCrO$_2$ in the ordered state below $T_{\rm{N1}}=24.2$ K are presented. The spectra are analyzed using a model Hamiltonian which includes intralayer-exchange up to the next-next-nearest neighbor and interlayer-exchange. We obtain a definite parameter set and show that exchange interaction terms beyond the next-nearest neighbor are important to describe the inelastic excitation spectrum. The magnetic ground state structure generated with our parameter set is in agreement with the structure proposed for CuCrO$_2$ from the results of single crystal diffraction experiments previously published. We argue that the role of the interlayer exchange is crucial to understand the incommensurability of the magnetic structure as well as the spin-charge coupling mechanism.