Impact of Fe/NaCl (0Â 0Â 1) interface structure on electronic, magnetic and spin-polarized transport properties of Fe/NaCl/Fe (0Â 0Â 1) heterojunctions: An ab initio study

Structural, electronic and spin-dependent transport properties of Fe/NaCl/Fe (0 0 1) tunnel junctions with c(2 × 2) structure are studied by means of first-principles calculations. Several Fe/NaCl (0 0 1) interfaces are considered and their stability is analyzed. The interfacial charge transfer has an important role in stabilizing Fe/NaCl (0 0 1) interfaces. Interfacial iron magnetic moments are enhanced over the bulk value. Fe induced gap states are observed in barrier layers on both Na and Cl ions. Small exchange couplings with exponential decays as function of the barriers thickness are evidenced. Resonant tunnelling plays a major role on the spin-polarized transport properties. High magnetoresistance ratios comparable to Fe/MgO/Fe junctions are predicted. Total energy calculations show that interfacial interdiffusion is not favourable but the disorder at interfaces may strongly affect the electronic transport properties. Absence of interfacial interdiffusion together with the small lattice mismatch between Fe and NaCl layers are important advantages of Fe/NaCl/Fe (0 0 1) junctions for the purpose of spintronic applications.