Growth properties of Ti/Co multilayers

Ti/Co multilayers with either wedge-shaped or constant-thickness Co sublaye rs were prepared using UHV DC/RF magnetron sputtering. The planar growth of the Co and Ti layers was confirmed by X-ray photoelectron spectroscopy and scanning tunnelling microscopy. Results on structural and magnetic studies showed that the cobalt sublayers grow on 2 and 5 nm titanium sublayers in the soft magnetic nanocrystalline phase up to a critical thickness d(crit) similar to 3.0 and 3.3 nm, respectively. For a thickness greater than d(cri t), the Co sublayers undergo a structural transition to the polycrystalline phase with much higher coercivity.