Role of electronegativity on the bulk modulus, magnetic moment and band gap of Co2MnAl based Heusler alloys

Abstract

In this paper, we have presented the comparative study of mechanical, electrical and magnetic properties of Co2MnAl1−xZx Heusler alloy with Z = Si, Ge and Ga and x = 0, 0.25, 0.75 and 1 using electronegativity (EN) model. We employed density functional theory for numerical calculations. It is found that Co2MnAl1−xZx with Z = Ga, Ge follow the Vegard's law while Co2MnAl1−xSix does not follow the same trend. Among all composition Co2MnAl.25Si.75 alloy is found to be more compressible. Electronic density distribution depicts the ionic nature of Co2MnAl1−xZx alloy systems. The Co2MnAl1−xZx with Z = Si, Ge possess larger magnetic moment and band gap with respect to Co2MnAl1−xGax system which results from the EN difference, degree of delocalization of valence electron, atomic size and atomic number, respectively. Keywords: Heusler alloy, Lattice parameter, Bulk modulus (BM), Magnetic moment, Band gap