Determination of spin pumping effect in CoFeB/Ir bilayer

• Published in: Journal of magnetism and magnetic materials Vol. 497; p. 165971
• Main Authors: Sun, Rui, Li, Yan, Xie, Z.K., Li, Yang, Zhao, Xiao-Tian, Liu, Wei, Zhang, Z.D., Zhu, T., Cheng, Zhao-Hua, He, Wei
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.03.2020; Elsevier BV
• Subjects: Broadband; Damping; Diffusion length; Ferromagnetic resonance; Ferromagnetism; Heavy metal; Heavy metals; Pumping; Resistance; Spin diffusion length; Spin pumping; Spin-orbit interactions; Spintronics; Thin film; Spin diffusion length; Spin pumping; Spintronics; Heavy metal; Thin film
• ISSN: 0304-8853; 1873-4766
• DOI: 10.1016/j.jmmm.2019.165971

•The spin diffusion length of Ir and the spin mixing conductance of CoFeB/Ir interface were obtained.•The spin mixing conductance is 2.14 × 1019 m−2 and the spin diffusion length is only 1.34 nm.•Ir possesses a strong spin-orbit coupling and is quite suitable for Ir-based spintronic materials engineering. The spin pumping effect of CoFeB/Ir bilayers has been investigated via the broadband ferromagnetic resonance measurement. With increasing the thickness of heavy metal Ir layer, the Gilbert damping factor of 8 nm CoFeB film increases from 7 × 10−3 to 1.1 × 10−2, and the additional damping factors induced by the spin pumping effect quickly reaches its saturation value. According to the spin pumping theory, the spin mixing conductance of CoFeB/Ir and the spin diffusion length of Ir were obtained. The spin mixing conductance is 2.14 × 1019 m−2. Furtherly, the spin diffusion length is only 1.34 nm, which is quite shorter compared with the heavy metal Pt. Our results reveal the existence of the strong spin-orbit coupling in the heavy metal Ir, which can be a potential material for the application in spintronic devices.