Disorder dependent half-metallicity in Mn2CoSi inverse Heusler alloy

Abstract

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 A2a-type and B2-type disorders destroy the half-metallicity whereas it sustains for all disorders concentrations in DO3a- and A2b-type disorder and for smallest disorder concentration studied in DO3b-type disorder. Lower formation energy/atom for A2b-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.