Morphology and magnetic structure of Fe/Cu(100)

Abstract

The structure and magnetism of epitaxially grown Fe films on Cu(100) at 300 K have been investigated in situ using reflection high-energy electron diffraction, low-energy electron diffraction, scanning tunnelling microscopy and magneto-optical Kerr effect. Based on a careful thickness calibration, the three well-known regions with distinct magnetic properties are determined accurately for Fe films on Cu(100). We claim that the traditional region II should be further divided into two parts: II(a) and II(b), where the former remains region II in the traditional sense but the latter is a transition region between regions II and III. A theoretically predicted temperature-driven martensitic phase transition from face-centred-cubic (fcc) Fe to body-centred-cubic Fe is indeed realized in the transition region II(b). In addition, the total magnetic moments as a function of film thickness and its temperature dependence have also been investigated. The results exclude the collinear type-1 antiferromagnetic configuration as the magnetic structure for fcc Fe films on Cu(100). It is proposed that a spin-density-wave state is responsible for the magnetic structure.