Surface roughness in Cu(100)/[Co/Cu]_n systems grown by ion-beam sputtering

Abstract

The development of surface roughness in Co/Cu systems was investigated through the use of in situ scanning tunneling microscopy. Multilayers and single layers of cobalt and copper were sequentially grown on a Cu(100) substrate. We show that the growth mode of cobalt on copper is quite different from that of copper on cobalt. We characterize these differences by looking at the lateral variations and obtaining a mean measure of island length. The cobalt tends to nucleate in small (<5 nm) islands. An overlayer of copper broadens this length scale while maintaining approximately the same peak-to-peak roughness of 5 monolayers. These growth mechanisms are shown to affect the way in which roughness propagates through multilayers. The impact of deposition temperature is also examined and seen to alter the degree of roughness in these samples. We conclude by discussing the implications for the magnetoresistance of these structures. © 1996 American Institute of Physics.