Ferromagnetic-resonance study of ultrathin bcc Fe(100) films grown epitaxially on fcc Ag(100) substrates

Abstract

Studies of ferromagnetic resonance lines at \ensuremath{\simeq}73 and \ensuremath{\simeq}36 GHz yield the static and dynamic parameters of ultrathin layers of bcc Fe(100) grown on fcc Ag(100) substrates and covered by fcc Au(100). Results for layer thicknesses of 28, 17, 5, and 3 monolayers when extrapolated to 2 monolayers indicate that the magnetization of bilayers of Fe should be perpendicular to the film. This indicates a large unexplained contribution to the magnetic anisotropy at or near the surfaces. A rapid increase in the Gilbert damping coefficient with decreasing film thickness reflects an enhanced role of spin-orbit coupling.