Half-metallicity and spin transport studies on quaternary CoCuMnSb Heusler alloy

Herein, the crystalline structure and spin transport properties of CoCuMnSb (CCMS) half-metallic Heusler alloy have been investigated with ab-initio calculations and nonequilibrium Green's function. Experimental and theoretical results reveal that CCMS alloy stabilizes in a highly ordered LiMgPdSn-type structure with lattice parameters of a = 6.113 Å and α = 90°, which match well with the reported lattice parameters of GaSb. Furthermore, the theoretical calculations indicate that CCMS exhibits perfect polarized spin at the Fermi level. Therefore, we have designed CCMS/GaSb heterostructure and CCMS/GaSb/CCMS magnetic tunnel junction (MTJ). Our architecture exhibits effective spin filtering and the MTJ produces a dramatic magnetoresistance ratio (~445). These outstanding properties marks CCMS as a strong system for applications in spintronics. •CoCuMnSb Heusler alloy exhibits 100% spin polarization at the Fermi level.•CoCuMnSb/GaSb heterostructure presents an excellent spin filtering effect.•CoCuMnSb/GaSb/CoCuMnSb magnetic tunnel junction has a large tunnel magnetoresistance ratio (~445).