Origin of the multiferroic-like properties of Er2CoMnO6

We report on the magnetoelectric properties of Er2CoMnO6. This compound adopts the structure of a double perovskite with a strong monoclinic distortion. Our specimen exhibits a nearly perfect Co-Mn order. It undergoes a ferromagnetic transition at TC~70 K due to the Co2+-O-Mn4+ ferromagnetic superexchange interaction. Below 30 K, the Er3+ moments start to order antiferromagnetically to the Co/Mn sublattice. Pyroelectric measurements reveal electrical polarization at low temperature but its strong dependence on the heating rate indicates the lack of a spontaneous ferroelectricity. Instead, electric polarization is derived from thermally stimulated depolarization currents