Large room-temperature intergrain magnetoresistance in double perovskite SrFe1-x(Mo or Re)xO3

Abstract

The intergrain magnetoresistance (IMR) effects in polycrystalline specimens of ordered perovskite SrFe1/2Mo1/2O3 and SrFe2/3Re1/3O3 were investigated. Large IMR at room temperature is found in SrFe1/2Mo1/2O3 where the magnetic coupling at insulating grain boundary is expected to be similar to the ferrimagnetic (FIM) coupling within metallic grains. These results, combined with previous reports, indicate that the field effect of electron tunneling in ferromagnetic (FM) metal-insulator-FM metal junctions can be greatly enhanced when the insulating layer is FM or FIM.