Influence of interfacial strain on spin reorientation in ultra-thin Co films

초록

We report results of an investigation of a spin reorientation transition in ultra-thin Co films from in-plane to out-of-plane. Eight monolayer thick Co films were epitaxially grown on Au single crystal films (the underlayer) and capped with a second layer of Au (the overlayer). For Au underlayers up to two monolayers thick, the spin orientation of the Co film was in the sample plane (in-plane). For thicker Au underlayers, e.g., five monolayers thick, an out-of-plane spin orientation was observed. Thus, for Co films of identical thickness, a spin reorientation from in-plane to out-of-plane can be induced by using thicker Au underlayers. We show the spin reorientation transition is controlled by the strain at the Co/Au interface. The strain-induced spin reorientation transition can also be observed in five monolayer thick Co films when capped with Cu rather than Au.