Substrate-Orientation Dependence on Structure and Magnetic Properties of MnAs Epitaxial Layers

Ferromagnetic MnAs layers were grown on (001), (111)A, and (111)B GaAs substrates by molecular-beam epitaxy at substrate temperatures (T s) in the range from 150 to 400° C. The crystal structure of the MnAs was NiAs type and its orientation was found to change depending on the substrate, (1101) for the (001) GaAs substrate and (0001) for the (111)A and (111)B substrates at T s between 300 and 400° C. Polar magneto-optical Kerr-effect measurement demonstrated a crystal-orientation dependence of Kerr rotation and Kerr ellipticity spectra of the MnAs epitaxial layers.