Half-metallic fully compensated ferrimagnetism and multifunctional spin transport properties of Mn3Al.

The complete (100%) spin polarization, zero net magnetic moment and high Curie temperature (605 K) make the recently fabricated half-metallic fully compensated ferrimagnet Mn3Al a promising spintronic material. In order to explore the potential applications in spintronic devices, in this work, we give a theoretical analysis for the Mn3Al/GaAs(0 0 1) heterostructure and the Mn3Al/GaAs/Mn3Al(0 0 1) magnetic tunnel junction. Using the first-principles calculations combined with nonequilibrium Green's function method, we demonstrate from the calculated bias-dependent spin transport properties that the heterostructure exhibits perfect spin filtering effect and spin diode effect, and the magnetic tunnel junction behaves a large tunnel magnetoresistance ratio (up to 10900%). The physical origins of these versatile spin transport properties are discussed in terms of the half-metallic band structure, the spin-dependent transmission spectra and the band-to-band transmission theory.