The effects of the interfacial structures on magnetoresistance in metallic superlattices

The effects of interfacial structures on the electronic transport properties in layered structures are investigated within the framework of the coherent potential approximation. In this paper, the two types of interfacial structures between a magnetic slab and a non-magnetic slab are assumed to exist in the superlattice. The first one, named the flat interface, is that the average distribution number of magnetic ions is nearly constant through the interfacial layers. The second, named the diffused interface, is that the average distribution number of magnetic ions decreases gradually in interfacial layers from the magnetic slab to the non-magnetic slab. It is shown within the framework of the mean field approximation that for the resistance the flat interface always shows larger absolute values than the diffused interface and that for the magnetoresistance ratio the value of it depends on the relative position of electron energy levels of magnetic and non-magnetic ions. Making a comparison between the experimental and calculational results, we can say that the spinflop scattering of conduction electrons due to the isolated localized spins is expected to play a major role in the case of the diffused interface where the superlattice shows the large magnetoresistance ratio.