Effect of Fe and Cr doping on electronic and magnetic properties of Inverse Heusler alloys: Mn₂CoCr_xGa_(1-x)and Mn₂CoFe_xGa _(1-x)

Mn and Co based Heusler alloys found to exhibit interesting electronic and magnetic properties. We have investigated the effect of electronic and magnetic properties on Mn₂CoGa after doping Fe and Cr. Entire calculations were performed through plane wave pseudo-potential method using quantum espresso.

From the calculation it is observed that the band gap of Mn₂CoGa shifted (increases) on 25% doping of Fe (or Cr) to its pristine form due to the effect of which shifting the band gap on the right side and shows perfect half-metallicity character. The band gap is found to be 0.307eV eV and 0.352eV for Fe and Cr doping respectively which is also greater than the minority band gap in the pristine (0.113 eV). The decreasing rate of bandgap is more in case of Fe doping than Cr doping. This maybe due to exchange splitting and coulomb repulsion competition. At this case system follows the Slater Pauling’s rule and hence gives rise to integer magnetic moments. If percentage of doping increases non-integer value of total spin magnetic moment is observed indicating that half-metallicity were destroyed. Doping in higher degree drastically increases the Magnetic moments.