Magnetic anisotropies of MnAs thin Films

L.B. STEREN , J. MILANO , M. MARANGOLO, M. EDDRIEF, V.H. ETGENS

Chile

Workshop; Latin American Workshop on Magnetism, Magnetic Materiales and their Applications.; 2005

LAW3M

Metallic MnAs is a promising material for uses in semiconductor-based spintronics devices. Bulk MnAs is ferromagnetic at room temperature and forms an hexagonal structure (alfa) whose lattice parameters match very well with those of GaAs. This material exhibits a  first-order phase transition at T¤=40 0 C between an hexagonal ferromagnetic phase (alfa) to a paramagnetic orthorrombic one (beta). MnAs thin films properties are strongly affected by the substrate material and its orientation. In films, the transition is much smoother and there is a coexistence of the alfa and beta phases in a finite temperature range below T¤. Moreover, the hexagonal phase is oriented perpendicular to the substrate surface for MnAs/GaAs(111) while it lays along the substrate plane for MnAs/GaAs(100). The magnetic anisotropy of the films evidence these results. In this work, a study of the magnetic behaviour of MnAs epitaxial layers will be presented. Magnetization and ferromagnetic resonance measurements give us an insight about the ordering of the Mn lattice and allow us to analyze the anisotropies of this system.(alfa) whose lattice parameters match very well with those of GaAs. This material exhibits a  first-order phase transition at T¤=40 0 C between an hexagonal ferromagnetic phase (alfa) to a paramagnetic orthorrombic one (beta). MnAs thin films properties are strongly affected by the substrate material and its orientation. In films, the transition is much smoother and there is a coexistence of the alfa and beta phases in a finite temperature range below T¤. Moreover, the hexagonal phase is oriented perpendicular to the substrate surface for MnAs/GaAs(111) while it lays along the substrate plane for MnAs/GaAs(100). The magnetic anisotropy of the films evidence these results. In this work, a study of the magnetic behaviour of MnAs epitaxial layers will be presented. Magnetization and ferromagnetic resonance measurements give us an insight about the ordering of the Mn lattice and allow us to analyze the anisotropies of this system.