Large room-temperature intergrain magnetoresistance in double perovskite SrFe1-x(Mo or Re)(x)O-3

Abstract

We report significant intergrain magnetoresistance (IMR) in polycrystalline double perovskites of SrFe1-x (Mo or Re)(x)O-3 at room temperature. Systematics of the temperature dependence of IMR indicates that the observed large room-temperature IMR in SrFe1/2Mo1/2O3 originates from the ferrimagnetic nature of insulating grain boundaries as well as the half-metallicity of this perovskite. Our results indicate that a new avenue for spin-polarized tunneling junctions is to utilize insulating interface layers with ferromagnetic or ferrimagnetic coupling. (C) 1999 American Institute of Physics. [S0003-6951(99)00412-X].