Disorder dependent half-metallicity in Mn2CoSi inverse Heusler alloy

Heusler alloys based thin-films often exhibit a degree of atomic disorder which leads to the lowering of spin polarization in spintronic devices. We present ab-initio calculations of atomic disorder effects on spin polarization and half-metallicity of Mn2CoSi inverse Heusler alloy. The five types of disorder in Mn2CoSi have been proposed and investigated in detail. The A2(a)-type and B2-type disorders destroy the half-metallicity whereas it sustains for all disorders concentrations in DO3a- and A2(b)-type disorder and for smallest disorder concentration studied in DO3b-type disorder. Lower formation energy/atom for A2(b)-type disorder than other four disorders in Mn2CoSi advocates the stability of this disorder. The total magnetic moment shows a strong dependence on the disorder and the change in chemical environment. The 100% spin polarization even in the presence of disorders explicitly supports that these disorders shall not hinder the use of Mn2CoSi inverse Heusler alloy in device applications. (C) 2013 Elsevier Inc. All rights reserved.