Tunable Anomalous Hall effect and structural properties in polycrystalline RF-sputtered Heusler Co₂MnGa films

We present transverse resistivity measurements in a set of ~0.5 micron thick Co₂MnGa films grown via RF sputtering. We show that the Anomalous Hall effect, evidenced by a dramatically enhanced transverse resistance at low magnetic fields that reaches a constant value as the magnetic field increases, can be tuned by varying the substrate temperature and the RF power during the film growth. The Hall constant at the zero magnetic field limit and the maximum Hall resistance achieved at high fields show a strong dependence on the growth parameters. The magnetic field that corresponds to the saturation of transverse resistance, on the contrary, appears to be relatively constant. We discuss the possible relationship between the morphology of the film grains and the crystalline order, both of which vary with the growth conditions, and the macroscopic transport properties of the films.