Structure, Magnetism, and Electronic Properties of Inverse Heusler Alloy Ti2CoAl/MgO(100) Herterojuction: The Role of Interfaces

Abstract

In this study, the interface structures, atom-resolved magnetism, density of states, and spin polarization of 10 possible atomic terminations in the Ti 2 CoAl/MgO(100) heterojunction were comprehensively investigated using first-principle calculations. In the equilibrium interface structures, the length of the alloy-Mg bond was found to be much longer than that of the alloy-O bond because of the forceful repulsion interactions between the Heusler interface atoms and Mg atoms. The competition among d-electronic hybridization, d-electronic localization, and the moving effect of the interface metal atoms played an important role in the interface atomic magnetic moment. Unexpected interface states appeared in the half-metallic gap for all terminations. The "ideal" half-metallicity observed in the bulk had been destroyed. In TiAl-Mg and AlAl-O terminations, the maximal spin polarization of about 65% could be reserved. The tunnel magnetoresistance (TMR) value was deduced to be lower than 150% in the Ti 2 CoAl/MgO(100) heterojunction at low temperature.

First-Principles Forecast of Gapless Half-Metallic and Spin-Gapless Semiconducting Materials: Case Study of Inverse Ti2CoSi-Based Compounds

“…Thus, Ti2.25Co0.75Si is a half-metallic ferromagnetic material with an integer magnetic moment of 7 μB (see Table 1). The calculated values of P were 98% for Ti2.25Co0.75Si0.5B0.5 and Ti2.25Co0.75Si0.5Ga0.5, and 96% for Ti2.25Co0.75Si0.5P0.5, and 100% for the other studied compounds in this work, where P = [N↑(EF) − N↓(EF)] / [N↑(EF) + N↓(EF)], and N↑,↓(EF) are the spin-dependent density of states at the Fermi level [39][40][41].…”

Special Issue on “Recent Advances in Novel Materials for Future Spintronics”

“…Wei et al [34] studied the interfacial electronic, magnetic, and spin transport properties of Mn 2 CoAl/Ag/Mn 2 CoAl current-perpendicular-to-plane spin valves (CPP-SV) based on density functional theory and non-equilibrium Green's function. Wu et al [35] conducted a comprehensive study of the electronic and magnetic properties of the Ti 2 CoAl/MgO (100) heterojunction with first-principles calculations. Ten potential Ti 2 CoAl/MgO (100) junctions are presented based on the contact between the possible atomic interfaces.…”