[18a-D704-1~11] 10.2 Fundamental and exploratory device technologies for spin

▲ [18a-D704-10] Orbital torque modulation by oxygen accumulation

〇Junyeon Kim¹, Jun Uzuhashi², Dongwook Go^3,4, Daegeun Jo⁵, Tadakatsu Ohkubo², Seiji Mitani², Hyun-Woo Lee⁵, YoshiChika Otani^6,1 (1.RIKEN-CEMS, 2.NIMS, 3.PGI-IAS, 4.Univ. Mainz, 5.POSTECH, 6.ISSP, Univ. Tokyo)

Keywords:Orbital torque, Orbital Rashba effect, Orbital current

Nowadays, orbital transport draws a great interest in terms of a promising mechanism of spin manipulation. Injected orbital into a magnetic layer exerts a torque which is called orbital torque. Different to the spin polarization, the orbital polarization has a broad material selection range, not requiring heavy elements or magnetic materials.
Here we find a significant orbital torque modulation by oxygen accumulation in CoFe/Cu/Al₂O₃ thin films. The oxygen accumulation is controlled by oxygen-incorporation exposure time or annealing temperature. We evaluate orbital torque using the spin torque ferromagnetic resonance (ST-FMR) technique. Remarkably, the orbital torque is drastically varied by the oxygen accumulation with a factor of around ~3. Further information will be provided during the presentation.