Electric field control and effect of Pd capping on magnetocrystalline anisotropy in FePd thin films: A first-principles study

P. V. Ong*, Nicholas Kioussis, P. Khalili Amiri, J. G. Alzate, K. L. Wang, Gregory P. Carman, Jun Hu, Ruqian Wu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

Using ab initio electronic structure calculations, we have investigated the effect of an electric field and of a heavy-metal cap of Pd on the magnetocrystalline anisotropy (MCA) of FePd ultrathin film. Analysis of the energy- and k-resolved distribution of the orbital character of the minority-spin band reveals that the perpendicular MCA of the uncapped film mainly arises from the spin-orbit coupling (SOC) between unoccupied Fe dxy and occupied Fe dx2-y2 states. On the other hand, the SOC between the Pd- and Fe-derived d states yields negative contributions to the MCA. We find that the sensitivity of the surface anisotropy energy to the applied electric field is 18 fJ/(Vm) and is due to changes in the occupation of the surface Fe atoms dx2-y2 and (dxz,dyz) orbitals. We demonstrate that the thickness of the Pd cap has a dramatic effect on the MCA and can even switch the magnetization from out-of- to in-plane orientation. The underlying origin is the change of the position and orbital character of the spin-polarized quantum well states induced in the Pd cap by varying its thickness. These results have important implications for exploiting heavy metals with large spin-orbit coupling (Ru, Pd, Ta, Pt, or Au) as contacts with ferromagnetic thin films to tailor the magnetic switching of spintronic devices by tuning the cap thickness.

Original languageEnglish (US)
Article number094422
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume89
Issue number9
DOIs
StatePublished - Mar 24 2014

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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