LAUSR

In spintronics, simultaneous realization of high tunneling magnetoresistance and low resistivity in magnetic tunnel junctions (MTJs) is challenging because insulating layers with higher barrier heights generally generate highly spin-polarized currents but increase resistivity. We overcome this trade-off relationship using Brillouin-zone-folded bands at the interfaces in the Fe/spinel ${\mathrm{MgGa}}_{2}{\mathrm{O}}_{4}/\mathrm{Fe}\phantom{\rule{0.16em}{0ex}}\mathrm{MTJ}$. Interfacial resonant states that enhance conductance are formed by folded bands, with Fe--O hybridization playing a key role in the resonant effect intensity at the Fermi level. The electronegativity of cation Ga in spinel oxide ${\mathrm{MgGa}}_{2}{\mathrm{O}}_{4}$ is found to be a crucial physical quantity to control an intensity of the interfacial-resonant effect from the comparative analysis with the ${\mathrm{MgAl}}_{2}{\mathrm{O}}_{4}$-based MTJ.