The spin injection efficiencies in epitaxial Co2MnSi (CMS)/Pt thin films were investigated in spin pumping configuration. The inverse spin Hall (effect) voltage significantly depends on the post-annealing temperature Ta of CMS, which shows one order larger values than those of Fe and CoFe at Ta = 400 °C. The effective spin mixing conductance derived by the analytical model reaches 6.5 × 1019 m−2. Our findings suggest that the Co-based Heusler alloys could be promising material candidates as the spin injection source with spin pumping.
