Resistivity minima in disordered Co2FeAl0.5Si0.5 Heusler alloy thin films

[Display omitted] •TS500 CFAS film has the highest B2 structural order and lowest residual resistivity.•Diffuson and WL effects (e-m and e-p scattering) dominate for T Tmin)•Phonon-induced non-spin-flip two-band (s↑↓- d↑↓) scattering accounts for.ρe-p•Thermal renormalization of spin-wave stiffness significantly contributes to.ρe-m(T)•Suppression of WL and e – m scattering by magnetic field results in negative MR. An exhaustive study of the effect of anti-site disorder on the ‘zero-field’, ρ(T, H = 0), and ‘in-field’, ρ(T, H = 80 kOe), electrical resistivity in 50 nm thick Co2FeAl0.5Si0.5 (CFAS) Heusler alloy thin films (deposited on the Si(100) or SiO2/Si(100) substrates at fixed substrate temperatures in the range 27°C≤TS≤550°C), has been carried out. Irrespective of the strength of disorder, resistivity goes through a minimum as a function of temperature at T = Tmin. With increasing substrate temperature, the crystalline order of the CFAS thin films improves so much so that the films deposited at 500 °C have the lowest anti-site disorder within the B2 structure and the least residual resistivity. A quantitative comparison of our results with the predictions of the existing theoretical models permits us to unambiguously identify the diffusive and ballistic transport mechanisms, responsible for ρ(T, H = 0) and ρ(T, H = 80 kOe) in different temperature ranges and accurately determine their relative magnitudes. The electron-diffuson (e – d) scattering and weak localization (WL) mechanisms, responsible for negative temperature coefficient of resistivity (TCR) for T