Spin transport properties of highly lattice-matched all-Heusler-alloy magnetic tunnel junction

A highly lattice-matched all-Heusler-alloy magnetic tunnel junction (MTJ) is proposed by associating half metallic CoFeTiSi electrode and non-magnetic semiconductor Fe2TiSi barrier. Based on the non-equilibrium Green's function combined with first-principles calculations, spin transport mechanism is studied by analyzing the transmission coefficient, local density of states, and scattering states. The calculated equilibrium tunnel magnetoresistance (TMR) ratio in CoFeTiSi/Fe2TiSi/CoFeTiSi reaches up to about 3.30 x 10(8)%, which is much higher than in CoFeTiSi/MgO/CoFeTiSi. The calculated scattering states reveal that CoFeTiSi/Fe2TiSi/CoFeTiSi MTJ possesses two transport channels, and the contribution of channel I to the total transport is about 80%, which plays a dominate role. The analyses on non-equilibrium spin transport properties reveal that CoFeTiSi/MgO/CoFeTiSi MTJ can output a high intensity transport current with complete spin polarization, and it can output a stable and highly efficient signal. The TMR ratio possesses an extremely large value of about 2.4 x 10(8)% and even the bias voltage increases to 0.2 V, exhibiting a robust current-driven stability.

Automated summary

A highly lattice-matched all-Heusler-alloy magnetic tunnel junction (MTJ) with a CoFeTiSi electrode and a Fe2TiSi barrier is proposed. The MTJ exhibits a high equilibrium tunnel magnetoresistance (TMR) ratio and has two transport channels, with channel I playing a dominant role. The non-equilibrium spin transport analysis shows that the MTJ can produce a highly polarized transport current and has good stability.