Tuning the magnetic properties by partial substitution of Cr in D022-Mn3Ga: A potential material for spin transfer torque applications

This report presents the effect of partial substitution of the Cr atom at the itinerant octahedral site (Y2b site) of D022-type Mn3Ga. The Cr introduces a reduction of magnetization due to the antiparallel alignment of Cr atoms at the itinerant site to Mn atoms at the localized site (X4d) with variation in mixed valence states (Mn4+ and Mn3+) from that of the pristine as revealed from the deconvolution of the Mn2p peak. The alloy possesses irreversible magneto-structural phase transformation during heating and cooling modes of temperature-dependent magnetization study. During heating, the magnetic interaction between Mn and Cr atoms possesses an abrupt change in magnetization over temperature, leading to Hopkinson’s like effect with magneto-structural transition temperature (Tc) ∼ 780 K, notably higher than the parent alloy. The thermal variation of uniaxial magnetocrystalline anisotropy ≈1.20-0.2 Merg/cc in addition to high coercivity (∼1.2–2.85 kOe) can be utilized as potential material for spin transfer torque-based memory applications.