Kim, JongHyuk Lee, DongJoon Lee, Kyung-Jin Ju, Byeong-Kwon Koo, Hyun Cheol Min, Byoung-Chul Lee, OukJae 2024-01-19T23:03:05Z 2024-01-19T23:03:05Z 2021-09-03 2018-04 2045-2322 https://pubs.kist.re.kr/handle/201004/121550 We investigate spin orbit torque (SOT) efficiencies and magnetic properties of Pt/GdFeCo/MgO multilayers by varying the thicknesses of GdFeCo and MgO layers. Our studies indicate that the ferrimagnetism in the GdFeCo alloy is considerably influenced by both thicknesses due to the diffusion of Gd atoms toward the MgO layer. Comparing to conventional Pt/ferromagnet/MgO structures, the Pt/GdFeCo/MgO exhibits a lower efficiency of SOTs associated with ferrimagnetic order and a similar magnitude of magnetic damping. The previous models that have been developed for rigid ferromagnets are inappropriate to analyze our experimental data, leading to an unphysical consequence of spin transmission larger than unity. Our results imply that the heavy-metal/ferrimagnet system is quite different from heavy-metal/ferromagnet systems in terms of magnetic dynamical modes, spin angular momentum transfer, and relaxation processes. English NATURE PUBLISHING GROUP Spin-orbit torques associated with ferrimagnetic order in Pt/GdFeCo/MgO layers Article 10.1038/s41598-018-24480-2 1 SCIENTIFIC REPORTS, v.8 SCIENTIFIC REPORTS 8 scie scopus 000430048000007 2-s2.0-85053128737 Multidisciplinary Sciences Science & Technology - Other Topics Article FERROMAGNETIC-RESONANCE MAGNETIC-RESONANCE RARE-EARTH METALS FILMS spin orbit torque magnetic damping ferrimagnet spin torque ferromagnetic resonance