Ferromagnetic resonance in ultrahigh vacuum: Effect of epitaxial overlayers on Fe

The analysis chamber of a Physical Electronics Model 400 Molecular Beam Epitaxy system is used to house a ferromagnetic resonance (FMR) probe. The sensitivity of FMR on Fe to surface structure and overlays of other materials is investigated. Surface sulfides, for example, increase the FMR linewidth. The elements Cr, Mn, and Ni grow epitaxially in the bcc phase on the (100) surface of Fe. MnO grows epitaxially from the Mn overlayers at room temperature. Only Ni has a significant effect on the position of the Fe  FMR lines. It seems reasonable to conclude from FMR line shifts that bcc Ni is ferromagnetic with a Curie temperature well above 80 K.