Correlation between magnetic and transport properties of Co/Ir/Co sandwiches and surface roughness

Co-3 nm/Ir-x/Co-3 nm sandwiches with 0.5, 1 and 1.5-nm thickness of Ir were deposited on glass substrates covered by a Fe-5 nm/Co-0.5 nm/Cu-3 nm layer , using the ion beam sputtering (IBS) technique. The maximum giant magnetor esistance and coupling strength were, respectively, 2% and -0.55 erg/cm(2). The magnetic and transport properties were investigated and correlated wit h atomic force microscopy measurements. The surface roughness was analyzed at each stage of the growth by calculating the root mean square (RMS) on su rfaces of 1 x 1 mum(2). The average roughness was small, approximately 0.3 nm, which is a necessary condition to observe an anti-ferromagnetic exchang e coupling in a sandwich stack. (C) 2000 Elsevier Science B.V. All rights r eserved.