Effect of disorder on the anomalous Hall conductivity of Co < inf > 2 < /inf > FeSi thin films

Abstract

The longitudinal resistivity and anomalous Hall resistivity of 50 nm Co2FeSi films deposited on Si (1 0 0) substrate at different temperatures have been investigated as functions of disorder. The film deposited at 450 °C has minimum disorder and the lowest temperature (Tmin ∼ 11 K) at which resistivity goes through a minimum as a function of temperature. The film with the highest disorder has the largest Tmin, residual resistivity and absolute value of resistivity at any given temperature. The resistivity data have been analyzed taking into account the contributions from electron-electron scattering, electron-phonon scattering and disorder-induced enhanced electron-electron interaction, which dominates at low temperatures. The effect of Tmin is observed in Hall resistivity for all the samples. Anomalous Hall conductivity (AHC) is extremely sensitive to the degree of disorder present in the films and has the value 180 S/cm at 300 K for the most ordered TS450 film, which tallies well with the theoretically calculated value for the Co2FeSi alloy with L21 structure. The influence of disorder on the longitudinal resistivity and anomalous Hall effect has been discussed in detail.