Fully epitaxial Fe(110)/MgO(111)/Fe(110) magnetic tunnel junctions: Growth, transport, and spin filtering properties

International audienceFully epitaxial Fe(110)/MgO(111)/Fe(110) magnetic tunnel junctions (MTJs) have been tested with respect to symmetry-enforced spin filtering. The Fe(110) electrodes exhibit Σ1↑ and Σ1↓ spin states, both crossing the Fermi level, but with a group velocity about 50% smaller for the minority states compared to the majority ones. These epitaxial but symmetry-mismatched MTJs yield tunneling magnetoresistance (TMR) values of 54% at 1.5 K and 28% at room temperature. The TMR value and the estimated tunneling spin polarization are consistent with a partial spin filtering due to the Σ1↑ states partially compensated by the Σ1↓ states