Magnetic interactions and electronic structure of \hbox {Pt}_{2}\hbox {Mn}_{1 x}\hbox {Y}_{x} \hbox {Ga (Y Cr and Fe)$Pt2Mn1 xYxGa (Y Cr and Fe) system: An ab initio calculation
First principles density functional theory based calculations have been carried out to predict the effects of Mn replacement by Fe and Cr on electronic as well as magnetic properties of \hbox {Pt}_{2}\hbox {MnGa}$Pt2MnGa and \hbox {Ni}_{2}\hbox {MnGa}$Ni2MnGa. All the materials studied here are predicted to have conventional Heusler alloy structure in their ground state and they are found to be electronically stable on the basis of their respective formation energy. The replacement of Mn by Fe leads to a ferromagnetic ground state whereas in case of Mn replacement by Cr an intrasublattice antiferromagnetic configuration has been observed to have lower energy. We study the magnetic exchange interaction between the atoms for the materials with ferromagnetic and antiferromagnetic configurations to show the effects of Fe and Cr substitution at Mn site on the magnetic interactions of these systems. Detailed analysis of electronic structure in terms of density of states has been carried out to study the effect of substitution.