14:00 〜 14:15
▲ [26p-E201-2] Determination of orbital torque efficiency in ferromagnet/Cu/Oxide thin films
キーワード：orbital torque, Spin manipulation, Rashba effect
The utilization of orbital angular momentum (OAM) provides a promising path for low-power-consumption spin manipulation. Recent studies show that an interaction between Cu and oxygen at an interface/surface such as Cu/Al2O3 leads to strong OAM polarization through the orbital Rashba effect, giving rise to a non-trivial torque (orbital torque, OT), 10-100 times more efficient than the conventional spin torque by the spin conversion [1,2]. Nevertheless, we still encounter plenty of issues to be addressed for further spintronic applications because of unconventional features of the OT.
We studied the OT for CoFe/Cu/OX (OX=MgO, SiO2, TiO2) ultrathin films. All the samples are prepared by the electron beam evaporation technique and photo-lithography. We measured the OT using the spin torque ferromagnetic resonance (ST-FMR) technique and found sizeable OT for all films (Fig. 1). Nonetheless, the magnitude of the OT varies depending on the capped oxide layer, and maximum OT appears for the SiO2 capped films. Considering pronounced OAM polarization at the Cu/OX interfaces, we speculate that the different Cu-oxygen interaction depending on the capped layer provides a critical role in determining the OT efficiency. Further information will be given during the meeting.
[1] J. Kim et al., Phys. Rev. B, 103, L020407 (2021).
[2] D. Go et al., Phys. Rev. B, 103, L121113 (2021).
We studied the OT for CoFe/Cu/OX (OX=MgO, SiO2, TiO2) ultrathin films. All the samples are prepared by the electron beam evaporation technique and photo-lithography. We measured the OT using the spin torque ferromagnetic resonance (ST-FMR) technique and found sizeable OT for all films (Fig. 1). Nonetheless, the magnitude of the OT varies depending on the capped oxide layer, and maximum OT appears for the SiO2 capped films. Considering pronounced OAM polarization at the Cu/OX interfaces, we speculate that the different Cu-oxygen interaction depending on the capped layer provides a critical role in determining the OT efficiency. Further information will be given during the meeting.
[1] J. Kim et al., Phys. Rev. B, 103, L020407 (2021).
[2] D. Go et al., Phys. Rev. B, 103, L121113 (2021).