Strong crystal anisotropy of magneto-transport property in Fe$_{3}$Si epitaxial films

We report transport study of the epitaxial Fe$_{3}$Si/GaAs heterostructures prepared by the molecular beam epitaxy growth. The temperature dependence of resistivity can be described as $T^{3}$ dependence in terms of Bloch-Gruneisen formula. Below 50 K, the $T^{3}$ term lent supports to the anomalous single-magnon scattering predicted for the half-metallic material. By changing the current direction from parallel to the magnetic hard axis to the magnetic easy axis, the anomalous zigzag magnetoresistance (MR) behavior can be altered to cos$^{2}$(\textit{$\theta $}$_{M})$ expected for the anisotropic MR behavior at high field $\sim $500 Oe, with a maximum and a minimum occurring at the magnetic field parallel and perpendicular to the current direction, respectively. However, at low field below 100 Oe, the MR showed an interesting step function-like dependence at a critical angle \textit{$\theta $}$_{critical, }$corresponding to the magnetic hard [110] axis. Our study showed unusually strong dependence of magneto-transport properties on crystal anisotropy in the plan of the epitaxial Fe$_{3}$Si/GaAs films.