Magnetic interface formation at Fe/Cr/Fe(100)

Photoemission magnetic dichroism of Fe and Cr 3p core levels was employed to investigate the magnetic order at the Fe/Cr/Fe(100) interface. For submonolayer and monolayer Fe coverages on Cr(100) the interface system appears magnetically frustrated, with no net magnetization along the parallel (antiparallel) direction of the substrate magnetization. The analysis of the Fe 3p photoemission dichroism allows to conclude that, at these low coverages, Fe is magnetically ordered but along an axis lying at 90 degrees from the substrate Fe(100) magnetization, favoring the interpretation of biquadratic coupling between the ultrathin iron overlayer and the bulk iron substrate, across the Cr interlayer.