Structural and magnetoresistive properties of Co/Cu multilayers

Abstract

Co/Cu multilayers (ML) were thermally evaporated at very low deposition rates on Si substrates covered with buffer layers of different metals (Ag, Cu, In, Pb, Bi). Structural characterisation of samples was performed by X-ray reflectometry (XRR), X-ray diffraction (XRD) and atomic force microscopy (AFM). Magnetoresistance measurements were carried out at room temperature using a standard four-probe DC method with current in the plane of the sample. It seems that a choice of buffer type has no significant effect on the magnitude of GMR. Since the thickness of single layers is of similar magnitude as the interfacial roughness in samples we suggest that the observed small value of GMR effect can be attributed rather to the interruption of film continuity and creation of magnetic bridges between Co layers, resulting in direct ferromagnetic coupling of magnetic films.