Magnetic domain formation in Fe films on Cr(100)

Magnetic domain images of thin (2 nm) Fe films on Cr(100) are presented. Up on cooling a single-domain state transforms into a state with a locally var ying in-plane magnetization direction. This transformation is partially rev ersible and highly reproducible. It is suggested that the in-plane rotation is driven by frustration that favors 90 degrees coupling, and that the loc al magnetization direction reflects mu m-scale variations of the atomic sca le roughness.