[16a-D704-1~10] 10.3 Spin devices, magnetic memories and storages

▲ [16a-D704-1] Post-annealing effect on voltage induced coercivity change in Pt/Ru/Co/CoO/TiO_x system

〇Tomohiro Nozaki¹, Jun Okabayashi², Shingo Tamaru¹, Makoto Konoto¹, Takayuki Nozaki¹, Shinji Yuasa¹ (1.AIST, 2.UTokyo)

Keywords:spintronics, voltage control

We have reported a large voltage induced H_c changes after optimal post-annealing in Pt/Ru/Co/CoO/amorphous TiO_x.[1] In this study, we investigated the effect of post-annealing on Pt/Ru/Co/CoO/amorphous TiO_x structures more detail. From magnetization curve under bias-voltage, we found that annealing at 350 ºC results in an increase in squareness and H_c, indicating an enhancement of PMA. Accompanying this improvement in PMA, a large voltage induced H_c change was observed in the 350 ºC annealed sample. STEM-EDX analysis confirmed that Co atoms diffused into Pt, and capacitance and XAS measurements suggest that a part of CoO is reduced, by the post-annealing. XMCD measurements revealed that annealing causes an increase in the interfacial orbital magnetic moment. Our results indicate that the PMA and VCMA at the Co/oxide upper interface are increased possibly due to the interdiffusion of Co and Pt, by post-annealing. [1] T. Nozaki et al., Sci. Rep. 11, 21448 (2021).