The FMR behavior of an ultrathin single Fe layer on a GaAs substrate

Single-layer Fe films 800 Å thick, with and without a 10-Å-thick Ag buffer layer, were prepared at various growtht emperature,T_g, on GaAs(001) substrates by molecular-beam epitaxy. For T_g around 200 °C, high-quality single crystal films were obtained without the Ag buffer layer. For T_g ⩽100 °C, a defect structure was observed in the iron layer. However, the addition of an ultrathin Ag buffer layer between GaAs and Fe has the desirable effects of eliminating the defect structure and significantly enhancing the FMR absorption.