Magnetization reversal of ultrathin Fe film grown on Si(111) using iron silicide template

Ultrathin Fe films were epitaxially grown on Si(111) by using an ultrathin iron silicide film with p(2\times2) surface reconstruction as a template. The surface structure and magnetic properties were investigated in situ by low energy electron diffraction (LEED), scanning tunnelling microscopy (STM), and surface magneto-optical effect (SMOKE). Polar SMOKE hysteresis loops demonstrate that the Fe ultrathin films with thickness t<6 ML (monolayers) exhibit perpendicular magnetic anisotropy. The characters of M--H loops with the external magnetic field at difference angles and the angular dependence of coercivity suggest that the domain-wall pinning plays a dominant role in the magnetization reversal process.