Perovskite oxide superlattices: Magnetotransport and magnetic properties

We have fabricated perovskite superlattices consisting of two ferromagnetic metallic oxides: La0.67Ca0.33MnO3 (LCMO) and SrRuO3 (SRO). We have investigated the magnetotransport and magnetic properties of a series of samples. in which the layer thickness of LCMO is tired and that of SRO varied from 0 to 20 unit cells. The magnetoresistance ratio in a superlattice can be increased by a factor of 3 at low temperatures over the MR ratio in pure LCMO film. This substantial enhancement is most likely caused by the interface spin-dependent scattering. The superlattice structure also increases T-c of LCMO by introducing a biaxial tension, and induces two consecutive switchings of magnetic easy axis direction with increasing SRO thickness.