Anomalous Hall effect in anatase Ti1−xCoxO2−δ at low temperature regime

Anomalous Hall effect (AHE) of a ferromagnetic semiconductor anatase Ti1−xCoxO2−δ thin film is studied from 10 K to 300 K. Magnetic field dependence of anomalous Hall resistance is coincident with that of magnetization, while the anomalous Hall resistance decreases at low temperature in spite of nearly temperature-independent magnetization. Anomalous Hall conductivity σAHE is found to be proportional to the square of Hall mobility, suggesting that charge scattering strongly affects the AHE in this system. The anatase Ti1−xCoxO2−δ also follows a scaling relationship to conductivity σxx as σAHE ∝ σxx , which was observed for another polymorph rutile Ti1−xCoxO2−δ, suggesting an identical mechanism of their AHE.