Abstract
Half-metallic magnets with metallic behavior in one spin channel and insulating in the other, have attracted considerable attention due to their potential application possibility. The spin-dependent nature of the carrier scattering due to half-metallic nature of these materials, allows for the resistance to be strongly influenced by the low magnetic field. However, the operating temperatures of such known materials are generally low, opening up the need for half-metallic magnets with high transition temperatures. The double perovskites having general formula A2BB'O6 with alternating ordered arrangement of two transition metal sites, B and B' offer an attractive possibility in this respect. Here, we consider the case of Sr2CrOsO6, which is a ferrimagnetic insulator with transition temperature (Tc) of 725 K, highest ever known in the oxide family, and show that moderate amount of La and Na doping at Sr site can drive the compound half-metallic with high Tc.