Magnetic properties of single-crystal {110} iron films grown on GaAs by molecular beam epitaxy (invited)

Abstract

Single-crystal {110} Fe films, grown for the first time by molecular beam epitaxy on GaAs, have been studied by a variety of techniques in order to determine the dependence of the magnetic properties upon film thickness L and quality, and an overview of these results is presented. The dependence of the ferromagnetic resonance (FMR) field upon its orientation in the (11̄0) plane was measured at 16.4 GHz and shows that the magnetically easy axis is [110] for L<50 Å and [001] for L≳150 Å. A theory of FMR which incorporates magnetocrystalline surface anisotropy is outlined. It successfully interprets the thickness dependence of the FMR data in the ultrathin (L≲50 Å) regime and shows them to be surface dominated. FMR data at 9.2 GHz, which contain both aligned and nonaligned resonance branches, are presented as a function L. In addition, the dependence of the branches on frequency f for 8 GHz<f<40 GHz along [001] and [110] are discussed.