Multiferroicity of CuCrO2 tested by electron spin resonance

We have carried out the electron spin resonance (ESR) study of the multiferroic triangular antiferromagnet ${\mathrm{CuCrO}}_{2}$ in the presence of an electric field. The shift of ESR spectra by the electric field was observed; the value of the shift exceeds that in materials with linear magnetoelectric coupling. It was shown that the low-frequency dynamics of magnetically ordered ${\mathrm{CuCrO}}_{2}$ is defined by joint oscillations of the spin plane and electric polarization. The results demonstrate an agreement with theoretical expectations of a phenomenological model [V. I. Marchenko, J. Exp. Theor. Phys. 119, 1084 (2014)].