Electric Control of Spin Helicity in Multiferroic Triangular Lattice Antiferromagnet CuCrO₂ with Proper-Screw Order

Abstract

We have carried out a spin-polarized-neutron study on multiferroic CuCrO₂ to clarify the origin of the ferroelectricity. The neutron results demonstrate that an incommensurate proper-screw magnetic structure of CuCrO₂ induces electric polarization. Not only the magnetic structure but also the oxygen location contributes to the ferroelectricity of CuCrO₂. The electric polarization of CuCrO₂ can be explained not by a conventional spin-current model but by a theoretical prediction proposed by Arima. The spin helicities of CuCrO₂ can be reversed by the reversal of the electric field E in the multiferroic phase.