<i>Ab initio</i> comparison of spin-transport properties in MgO-spaced ferrimagnetic tunnel junctions based on Mn₃Ga and Mn₃Al

We report on first-principles spin-polarised quantum transport calculations (from NEGF + DFT) in MgO-spaced magnetic tunnel junctions (MTJs) based two different Mn-based Heusler ferrimagnetic metals, namely Mn3Al and Mn3Ga their tetragonal DO22 phase. The former is a fully compensated half-metallic ferrimagnet, while the latter low-moment high-spin-polarisation both with small lattice mismatch from MgO. In identical symmetric asymmetric interface reconstructions across 3-monolayer thick MgO barrier for ferrimagets, linear response (low-voltage) spin-transfer torque (STT) tunneling magneto-resistance (TMR) effects are evaluated. A larger staggered in-plane STT found case, vanishes quickly away (similarly to ferromagnetic MTJs). roles reversed TMR, which practically 100% Mn3Al-based MTJs (using conservative definition) as opposed 60% case. weak dependence exact reconstruction would suggest Mn3Ga–Mn3Al solid solutions possible route towards optimal trade-off of TMR low-bias, low-temperature regime.