Giant Magnetoresistance at the Interface of Iron Thin Films

Ag/Fe/Ag and Cr/Fe/Cr trilayers with a single $25nm$ thick ferromagnetic layer exhibit giant magnetoresistance (GMR) type behavior. The resistance decreases for parallel and transversal magnetic field alignements with a Langevin-type magnetic field dependence up to B=12 T. The phenomenon is explained by a granular interface structure. Results on Fe/Ag multilayers are also interpreted in terms of a granular interface magnetoresistance.