Spin-orbit coupling effect by minority interface resonance states in single-crystal magnetic tunnel junctions

Abstract

Spin-orbit coupling (SOC) related to the minority interface resonance states (IRSs) of Fe(001) has been evidenced in full-epitaxial Fe(001)/MgO/Fe magnetic tunnel junctions (MTJs) from magnetotransport experiments correlated to theoretical ab initio calculations. We show that the SOC effect strongly depends on the symmetry composition of the IRS, which has been skillfully engineered via the interfacial chemical structure in the Fe(001)/MgO stack. The SOC scattering is enhanced between the majority ${\ensuremath{\Delta}}_{1}$ and minority ${\ensuremath{\Delta}}_{5}$ band near the Fermi level when presenting a ${\ensuremath{\Delta}}_{5}$ symmetry dominant IRS at the Fe/MgO interface. Our results validate the interplay between SOC and IRSs, which gives further understanding of the mechanisms responsible for the tunneling anisotropic magnetoresistance and the large perpendicular magnetic anisotropy at the Fe/MgO interface.