Magnetic-Structure-Stabilized Polarization in an Above-Room-Temperature Ferrimagnet

摘要

Above-room-temperature polar magnets are of interest due to their practical applications in spintronics. Here we present a strategy to design high-temperature polar magnetic oxides in the corundum-derived A2BB'O6 family, exemplified by the non-centrosymmetric (R3) Ni3TeO6-type Mn~(2+)2Fe~(3+)Mo~(5+)O6, which shows strong ferrimagnetic ordering with T_C = 337K and demonstrates structural polarization without any ions with (n—1)d~(10)ns~0, d~0, or stereoactive lone-pair electrons. Density functional theory calculations confirm the experimental results and suggest that the energy of the magnetically ordered structure, based on the Ni3TeO6 prototype, is significantly lower than that of any related structure, and accounts for the spontaneous polarization (68 μCcm~(-2)) and non-centrosymmetry confirmed directly by second harmonic generation. These results motivate new directions in the search for practical magnetoelectric/multiferroic materials.