TY - JOUR
T1 - Electric field control and effect of Pd capping on magnetocrystalline anisotropy in FePd thin films
T2 - A first-principles study
AU - Ong, P. V.
AU - Kioussis, Nicholas
AU - Amiri, P. Khalili
AU - Alzate, J. G.
AU - Wang, K. L.
AU - Carman, Gregory P.
AU - Hu, Jun
AU - Wu, Ruqian
PY - 2014/3/24
Y1 - 2014/3/24
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=84898729252&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84898729252&partnerID=8YFLogxK
U2 - 10.1103/PhysRevB.89.094422
DO - 10.1103/PhysRevB.89.094422
M3 - Article
AN - SCOPUS:84898729252
VL - 89
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
SN - 1098-0121
IS - 9
M1 - 094422
ER -