Magnetic field controlled reversal of ferroelectric polarization in conical spin ordered multiferroics : Monte Carlo simulation

Abstract

To understand the fascinating ultiferroicity observed in CoCr₂O₄, Monte Carlo simulation is performed on a three-dimensional spinel lattice with classical Heisenberg spins. The conical spin order is confirmed to be the origin of the peculiar magnetoelectric behavior with coexisting magnetization and ferroelectric polarization. Furthermore, the simultaneous reversals of magnetization and polarization controlled by the external magnetic field are reproduced, consisting with the experimental observation qualitatively. It is revealed that, from the microscopic structures of spins, the axis of spin cone provides a “handle,” with which the magnetization and polarization can be reversed by the magnetic field easily.