Identifying the multiferroic phase of doped CuFeO_2 using inelastic neutron scattering

TL;DR

This study uses inelastic neutron scattering to identify the multiferroic phase in Ga-doped CuFeO_2, revealing a distorted screw-type spin structure and a unique magnetoelectric coupling mechanism.

Contribution

It provides the first detailed dynamical fingerprint of the multiferroic ground state in doped CuFeO_2, challenging existing models of magnetoelectric coupling.

Findings

Identified a distinct spin excitation spectrum for the multiferroic phase.

Discovered a distorted screw-type spin configuration.

Proposed a new mechanism for magnetoelectric coupling.

Abstract

We report inelastic neutron scattering measurements that provide a distinct dynamical "fingerprint" for the multiferroic ground state of 3.5% Ga-doped CuFeO_2. The complex ground state is stabilized by the displacement of the oxygen atoms, which are also responsible for the multiferroic coupling predicted by Arima. By comparing the observed and calculated spectrum of spin excitations, we conclude that the magnetic ground state is a distorted screw-type spin configuration that requires a mechanism for magnetoelectric coupling different from the generally accepted spin-current model.