2018/10/09 by Mario Galante, Matthew O. A. Ellis, Stefano Sanvito · 1 citation
Engineering · Physics and Astronomy · #Algorithm #Computer science #Database #Magnetic properties of thin films #Molecular Junctions and Nanostructures #Physics #Quantum and electron transport phenomena #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevb.99.014401
published as Phys. Rev. B 99, 014401 (2019) · 8 pages, 7 figures
arxiv created 2018/10/09 · openalex created_date 2018/10/26 · openalex publication_date 2019/01/02 · arxiv updated 2019/01/09 · openalex updated_date 2026/08/05
We present an ab initio study of the spin-transfer torque in Fe/MgO/FePt/Fe magnetic tunnel junctions. We consider an FePt film with a thickness up to six unit cells, either in direct contact with the MgO spacer or with an intercalated ultrathin Fe seed layer. We find that in the FePt layer the torque is not attenuated as strongly as in the case of pure Fe. Moreover, in FePt the torque alternates sign at the Fe and Pt atomic planes throughout the stack for all FePt thicknesses considered. Finally, when Fe is intercalated between MgO and L10 FePt, the torque is sharply attenuated, and it is transferred to FePt only for an Fe seed layer that is less than two atomic planes thick. We attribute these features to the different spatial profiles of the exchange and correlation field and the induced nonequilibrium spin accumulation. The calculated tunneling magnetoresistance of the Fe/MgO/FePt/Fe junctions studied is enhanced with respect to the one of Fe/MgO/Fe, while it is reduced with Fe intercalation. Our work shows that L10 FePt junctions can be promising candidates for current-operated magnetic devices and that the magnetic texture at the atomic scale has an important effect on the spin-transfer torque.