Interface magnetic properties of epitaxial Fe-InAs heterostructures

The growth and interface magnetic properties of epitaxial Fe films grown on InAs (100)-4 x 2 have been studied using low-energy electron diffraction, in situ magneto-optical Kerr effect, and X-ray magnetic circular dichronism. The magnetic properties at room temperature were found to proceed via three phases with thickness; a nonmagnetic phase, a superparamagnetic phase, and a ferromagnetic phase. The initial ferromagnetic phase might be stabilized by interparticle interactions. The films show bulk-like spin moments of 1.90+/-0.15 mu(B) with the thickness above about 20 ML and a large enhancement similar to 260% of the ratio of orbital versus spin moment in the ultrathin region.