Structural, magnetic, electronic, and spin transport properties of epitaxialFe3Si∕GaAs(001)

We report experimental results on the structural, magnetic, electronic, and spin transport properties of a $21\mathrm{nm}$ ${\mathrm{Fe}}_3\mathrm{Si}∕\mathrm{GaAs}\left(001\right)$ heterostructure epitaxially grown by coevaporation. High-resolution x-ray diffraction shows an almost stoichiometric film, which is lattice matched in-plane to the $\mathrm{GaAs}$ substrate and therefore slightly tetragonal distorted. Polarized neutron reflectometry measurements yield a magnetic moment of $\left(1.107\pm 0.014\right){\mu }_{\mathrm{B}}$ per atom at room temperature (RT), while superconducting quantum interference device magnetometry yields a magnetic moment of $\left(0.9\pm 0.1\right){\mu }_{\mathrm{B}}$ per atom at RT, both close to the bulk value. Magneto-optic Kerr effect measurements show that this system has in-plane cubic anisotropy with easy axes along the $⟨100⟩$ directions and a cubic anisotropy constant $K_1=\left(3.1\pm 0.6\right)\times {10}^4\mathrm{erg}∕{\mathrm{cm}}^3$ at RT. A resistivity of $\left(4.1\pm 0.4\right)\times {10}^{-7}\Omega \mathrm{m}$ in the ${\mathrm{Fe}}_3\mathrm{Si}$ film was measured, which is close to the bulk value. Optical spin orientation in the $\mathrm{GaAs}$ was used for spin transport measurements and spin detection is demonstrated at RT for this system. Point contact Andreev reflection spectroscopy was used to determine the spin polarization of the transport current, yielding $P=\left(45\pm 5\right)\%$.