  A wide variation in the disorder strength, as inferred from an order of
magnitude variation in the longitudinal resistivity of Co2FeSi (CFS) Huesler
alloy thin films of fixed (50 nm) thickness, has been achieved by growing these
films on Si(111) substrates at substrate temperatures ranging from room
temperature (RT) to 600 C. An in-depth study of the influence of disorder on
anomalous Hall resistivity,longitudinal resistivity(LR) and magnetoresistance,
enabled by this approach, reveals the following. The side-jump mechanism gives
a dominant contribution to anomalous Hall resistivity (AHR) in the CFS thin
films, regardless of the degree of disorder present. A new and novel
contribution to both LR and AHR characterized by the logarithmic temperature
dependence at temperatures below the minimum, exclusive to the amorphous CFS
films, originates from the scattering of conduction electrons from the
diffusive hydrodynamic modes associated with the longitudinal component of
magnetization, called diffusons. In these amorphous CFS films, the
electron-diffuson, e d, scattering and weak localization (WL) mechanisms
compete with that arising from the inelastic electron magnon, e m, scattering
to produce the minimum in longitudinal resistivity, whereas the minimum in AHR
is caused by the competing contributions from the e d and e m scattering, as WL
does not make any contribution to AHR. In sharp contrast, in crystalline films,
enhanced electron electron Coulomb interaction (EEI), which is basically
responsible for the resistivity minimum, makes no contribution to AHR with the
result that AHR does not exhibit a minimum.
