Thermal Magnetic-Relaxation In Quasi-2-Dimensional Fe Films

Several Fe(110)/Ag(111) superlattices with the Fe component 2 monolayers thick and the Ag component of varying thickness were produced by molecular-beam epitaxy. The Curie temperature was found to be higher than 500 K and a central feature in the M\"ossbauer spectra is shown to come from thermal magnetic relaxation of Fe islands. The magnetic hyperfine field has a linear temperature dependence and this is explained by a simple model based on the island structure of the Fe.