Structural, magnetic and transport properties of Co₂FeSi Heusler films

We report the deposition of thin Co2FeSi films by RF magnetron sputtering. Epitaxial (1 0 0)-oriented and L21 ordered growth is observed for films grown on MgO (1 0 0) substrates. (1 1 0)-oriented films on {\rm Al}_2{\rm O}_3\,(1\,1\,\bar{2}\,0) show several epitaxial domains in the film plane. Investigation of the magnetic properties reveals a saturation magnetization of 5.0 µB/fu at low temperatures. The temperature dependence of the resistivity ρxx(T) exhibits a crossover from a T3.5 law at T < 50 K to a T1.65 behaviour at elevated temperatures. ρxx(H) shows a small anisotropic magnetoresistive effect. A weak dependence of the normal Hall effect on the external magnetic field indicates the compensation of electron and hole like contributions at the Fermi surface