Linear Magnetoelectric Effect in Topological Antiferromagnet Cu$_3$TeO$_6$

Abstract

We report on linear magnetoelectric effect observed by the static electric polarization measurements in external magnetic field up to 12 T on topological multidomain antiferromagnet Cu3TeO6. The polarization is non-zero only below the Néel temperature and for E ⊥ H. The magnetization data show spin reorientation taking place already in H < 1 T. This is fully captured by the anisotropic Heisenberg spin Hamiltonian, revealing the change of the magnetic point group from 3' in the ground state to m in the applied magnetic field, in agreement with the observed magnetoelectric effect. Both point groups allow the ferrotoroidic order which could be a source of magnetoelectric effect in this system. Our results establish Cu3TeO6 as a playground for the study of magnetoelectric topological antiferromagnets and a host of several phenomena which are of interest for future spintronic devices.