MAGNETIC-PROPERTIES OF EPITAXIAL SINGLE-CRYSTAL ULTRATHIN FE3SI FILMS ON GAAS (001)

Magnetic properties of Fe3Si films with thickness from 2 to 210 monolayers (ML) epitaxially grown on GaAs (001) were studied using a superconducting quantum interference device and alternating gradient force magnetometers. Growth of these single-crystal intermetallic compound films were carried out in a multichamber molecular beam epitaxy (MBE) system. The samples were covered in situ with Au 50 angstrom thick to prevent oxidation when the samples were removed from the MBE chamber. All the films are ferromagnetic even for samples as thin as 2 ML. The easy magnetization direction of the films is parallel to the film surface. The magnetic coercivity forces (H(c)) of the samples increase as the film thickness decreases to 10 ML, and then decrease when the film thickness decreases further to 2 ML.