The correlation between an ad-layer-induced spin reorientation transition (SRT) and the ad-layer-induced structural relaxation is investigated by combined in situ surface x-ray diffraction and magneto-optical Kerr-effect experiments on $\mathrm{N}\mathrm{i}/\mathrm{F}\mathrm{e}/\mathrm{N}\mathrm{i}(111)$ layers on W(110). The Fe-induced SRT from in-plane to out-of-plane, and the SRT back to in-plane upon subsequent coverage by Ni, are each accompanied by a small lattice relaxation of at most 0.002 Å. Such a small strain variation excludes a magnetoelasticity driven SRT, and we suggest the interface anisotropy as a possible driving force.

• Received 14 January 2004

DOI:https://doi.org/10.1103/PhysRevLett.93.156105