Role of Mn antisite defects on half-metallicity in Co2MnSi Heusler alloy

Accurate first-principles FLAPW calculations performed for Mn antisite defects in CO2MnSi alloy show that (i) the low defect formation energy results in a high concentration of Mn antisites during growth, in excellent quantitative agreement with experiments and (ii) half-metallicity - typical of bulk Co2MnSi - is kept, with the disorder resulting in a small increase of the spin-gap. These findings indicate that other kinds of defects or surface effects should be invoked in order to explain the observed reduced spin-polarization. (C) 2004 Elsevier B.V. All rights reserved.