Magnetic anisotropy of epitaxial iorn films on single-crystal MgO(001) and Al_2O_3(1120) substrates

摘要

The ferromagnetic resonance and magnetization of single-crystal thin (27-100 A films grown in the (110) direction are measured in the temperature range 20-400 K. The films are prepared by molecular-beam epitaxy on single-crystal sapphire Al_2O_3(1120) substrates with a Nb(110) buffer layer. The angular dependence of the parameters of the ferromagnetic resonance spectrum is observed to have a 180 deg character when the static magnetic field is rotated in the plane of the sample. It is established that this angular dependence can be described on the assumption that the lattice distortions are essentially trigonal. A comparative analysis of previous data for Fe(001) films with the data for Fe (110) films shows that the source of the corrections to the cubic anisotropy constant is the characteristic distribution of the strains along the thickness of the film.