Eur. Phys. J. B (2017) 90: 236
https://doi.org/10.1140/epjb/e2017-80461-4

Regular Article

Dielectric properties of multiferroic CuCrO₂

¹ University of Architecture, Civil Engineering and Geodesy, Department of Physics, 1046 Sofia, Bulgaria
² University of Forestry, Faculty of Forest Industry, 1756 Sofia, Bulgaria
³ Martin-Luther-University, Institute of Physics, 06120 Halle, Germany
⁴ University of Sofia, Department of Physics, 1164 Sofia, Bulgaria

^a e-mail: julia@phys.uni-sofia.bg

Received: 7 August 2017
Received in final form: 5 October 2017
Published online: 4 December 2017

Abstract

We propose a microscopic model in order to study the multiferroic properties of the triangular compound CuCrO₂ taking into account antiferromagnetic interactions in the ab plane, spin-phonon interactions and quadratic magnetoelectric (ME) coupling. The temperature and magnetic field dependence of the polarization P_ab and dielectric constant ϵ_ab is calculated. P_ab increases when h is parallel to its direction and decreases when h is perpendicular to it. We show that ϵ_ab has a kink near the magnetic phase transition T_N = 24 K which disappears with increasing of an external magnetic field h_ab. This behavior is an evidence for a strong ME coupling and in qualitative agreement with the experimental data.