PERPENDICULAR SURFACE MAGNETIC-ANISOTROPY IN ULTRATHIN EPITAXIAL FE FILMS

The in situ surface magneto-optic Kerr effect is used in conjunction with low-energy electron diffraction and Auger characterizations to study the surface magnetic anisotropy of ultrathin Fe films for various epitaxial structures: face-centered-cubic (fee) Fe(100) on Cu( 100). fee Fe(111) on Ru(0001), body-centered-tetragonal (bet) Fe(100) on Pd(100), and body-centered-cubic (bcc) Fe(100) on Au(100). All of these films exhibit a universal behavior of perpendicular spin orientations below a critical thickness of six monolayers (ML) or less, in spite of their structural differences, suggesting a surface electronic as opposed to geometric origin of the magnetic anisotropy. These films differ in their monolayer-range magnetic properties due to interdiffusion and electronic interactions across the interface. Fe/Pd(100) and Fe/Au(100) exhibit submonolayer ferromagnetism and growth-temperature dependent magnetic anisotropy, while < 2 ML Fe/Ru(0001) lacks a ferromagnetic signature. © 1990, American Vacuum Society. All rights reserved.