Anisotropic Magnetoresistance in Co2MnGa Heusler Alloy Films in Near-zero Magnetic Field

We present precision magneto-transport measurements in 0.5 micron thick Co2MnGa films grown on sapphire substrates via magnetron sputtering. The sample is a Hall bar with dimensions 1 x 3 mm. At magnetic fields B between zero and approximately 500 Gauss, we observe a pronounced reduction in the sample resistance of order of 1-5 parts in 10,000, approximately quadratic in B, when the magnetic field is orthogonal to the film plane. This change is at least an order of magnitude larger than that with the magnetic field oriented along the direction of the sample current. We also present data for the Hall coefficient and discuss the implications of the findings for assessing magnetic order, including the formation of zero-dimensional topological textures (skyrmions), in these films.