Magnetotransport in ferromagnetic Mn₅Ge₃, Mn₅Ge₃C₀̣₈ and Mn₅Si₃C₀̣₈ thin films

The electrical resistivity, anisotropic magnetoresistance (AMR), and anomalous Hall effect of ferromagnetic Mn5Ge3, Mn5Ge3C0.8, and Mn5Si3C0.8 thin films has been investigated. The data show a behavior characteristic for a ferromagnetic metal, with a linear increase of the anomalous Hall coefficient with Curie temperature. While for ferromagnetic Mn5Si3C0.8 the normal Hall coefficient R-0 and the AMR ratio are independent of temperature, these parameters strongly increase with temperature for Mn5Ge3Cx films. This difference is presumably due to the different lattice parameters and different atomic configurations of the metalloids Ge and Si affecting the electronic band structure. The concomitant sign change of R-0 and the AMR ratio with temperature observed for Mn5Ge3Cx films is discussed in a two-current model indicating an electronlike minority-spin transport at low temperatures.