GMR versus interfacial roughness induced from different buffers in (Co/Cu)ML

The correlation between the giant magnetoresistance Delta R/R, at the first maximum of the oscillating thickness dependence of the magnetoresistance ( MR), and the structural and magnetic parameters has been investigated in (C o/Cu) multilayers (ML) deposited by the unusual RF sputtering method. Diffe rent textures and interface roughnesses have been induced from magnetic (Fe , Co) and non-magnetic (Cu, Al, Ta, Cr) buffers. The MR is independent of t he ML texture and grain size but presents a strong correlation with the int erface as deduced from small and large angle XRD and AFM. In high roughness ML the evolution, under increasing applied field, of Delta R/R versus (M/M -s)(2) presents a strong deviation from a standard linear dependence. Such a deviation is attributed to the presence of Co granules in the Cu or/and t he buffer matrices when strong interface disorder is induced in the samples . (C) 1999 Published by Elsevier Science B.V. All rights reserved.