Magnetic Anisotropies in Ultra-Thin Iron Films Grown on the Surface-Reconstructed GaAs Substrate

Abstract

Magnetic anisotropies of epitaxial ultra-thin iron films grown on the surface reconstructed GaAs substrate have been studied. Ferromagnetic resonance (FMR) technique has been exploited to determine magnetic parameters of the films in the temperature range 4-300 K. The unusual angular dependence of FMR spectra allowed us to build precise model of the magnetic anisotropies of the studied systems. Presence of strong perpendicular anisotropy have been deduced. Switching of the principal anisotropy axes has been observed in the double ferromagnetic-layer sample. It has been attributed to drastic relaxation of the uniaxial component of anisotropy induced by the surface reconstruction of the substrate. The linear variation of magnetic anisotropy parameters with the temperature has been observed and discussed in terms of magneto-elastic anisotropies controlled by thermal expansion coefficients of the materials in a contact.