Interface modification in Fe/Cr epitaxial multilayers using swift heavy ion irradiation

Effect of 100 MeV Au ions irradiation on the interface structure and magneto transport properties of Fe/Cr epitaxial multilayers: MgO(0 0 1)/Cr (100 Å)/[Fe (30 Å)/Cr (12 Å)]20, have been studied. Interface structure is characterized by X-ray reflectivity and X-ray diffuse scattering measurements. In order to enhance the contrast between Fe and Cr layers, measurements are done at the X-ray energy just below the absorption edge of the iron. Diffuse scattering measurements show that the irradiation results in a substantial decrease in the in-plane correlation length of the roughness, while the roughness itself changes only by a small amount. Further, measurements at different values of qz suggest that the variations take place mainly in the uncorrelated part of the roughness. Giant magnetoresistance measurements in the irradiated multilayer suggest that it is mainly affected by the change in root mean square roughness and is influenced only weakly by variation in the in-plane correlation length.