Magnetism driven ferroelectricity above liquid nitrogen temperature in Y2CoMnO6

We report multiferroic behaviour in double perovskite Y2CoMnO6 with ferroelectric transition temperature T-c = 80 K. Both X-ray diffraction and neutron scattering data confirm a centrosymmetric crystal structure of space group P2(1)/n at room temperature. The saturation polarization and magnetization are estimated to be 65 mu C/m(2) and 6.2 mu(B)/f.u. respectively. The magnetoelectric coupling parameter, on the other hand, is small as a 5 T field suppresses the electric polarization by only similar to 8%. The origin of ferroelectricity is associated with magnetic ordering of Co2+ and Mn4+ moments in up arrow up arrow-down arrow down arrow arrangement. A model based on exchange-striction is proposed to explain the observed high temperature ferroelectricity. (C) 2013 AIP Publishing LLC.