Magnetoelectric properties of multiferroic CuCrO 2 studied by means of ab initio calculations and Monte Carlo simulations
Résumé
Motivated by the discovery of multiferroicity in the geometrically frustrated triangular antiferromagnet CuCrO 2 below its Néel temperature T N , we investigate its magnetic and ferroelectric properties using ab initio calculations and Monte Carlo simulations. Exchange interactions up to the third nearest neighbors in the ab plane, interlayer interaction, and single ion anisotropy constants in CuCrO 2 are estimated by a series of density functional theory calculations. In particular, our results evidence a hard axis along the [110] direction due to the lattice distortion that takes place along this direction below T N. Our Monte Carlo simulations indicate that the system possesses a Néel temperature T N ≈ 27 K very close to the ones reported experimentally (T N = 24-26 K). Also we show that the ground state is a proper-screw magnetic configuration with an incommensurate propagation vector pointing along the [110] direction. Moreover, our work reports the emergence of spin helicity below T N which leads to ferroelectricity in the extended inverse Dzyaloshinskii-Moriya model. We confirm the electric control of spin helicity by simulating P-E hysteresis loops at various temperatures.
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