Structural, electronic and magnetic properties and pressure-induced half metallicity in double perovskite Ca2AOsO6 (A = Cr, Mo)

Ca2CrOsO6 was synthesized recently and measured to be an insulating ferrimagnet with a high magnetic ordering temperature of 490 K. To design a half metal, we substituted Cr with Mo and performed an investigation on Ca2AOsO6 (A = Cr, Mo) by using the density functional theory. However, Ca2MoOsO6 is an insulator with a small band gap in one spin direction. By applying external pressure, the small gap can be closed, making Ca2MoOsO6 a compensated half metal. The estimated Tc for Ca2MoOsO6 under pressure is higher than the room temperature. Therefore, we expect that Ca2MoOsO6 would be promising compound for spintronic devices.