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Improvement of the Effective Spin Hall Angle by Inserting an Interfacial Layer in Sputtered BiSb Topological Insulator (Bottom)/Ferromagnet With In-Plane Magnetization

2021; IEEE Magnetics Society; Volume: 58; Issue: 4 Linguagem: Inglês

10.1109/tmag.2021.3115169

1941-0069

Julian Sasaki, Ho Hoang Huy, Nguyen Huynh Duy Khang, Pham Nam Hai, Quang Le, Brian York, X. Liu, Son Le, C. Hwang, M. Ho, H. Takano,

Atomic and Subatomic Physics Research

The topological insulator BiSb is promising for spin-orbit torque applications thanks to its high electrical conductivity and giant spin Hall effect. Previous works have reported a large spin Hall angle for BiSb deposited on top of a ferromagnetic layer with perpendicular magnetic anisotropy. However, since BiSb has large surface roughness, obtaining a large spin Hall angle in BiSb (bottom)/ferromagnet (FM) is more challenging than in FM/BiSb (top) structures, especially when the FM layer is very thin. Here, we investigate the role of an interfacial layer on the effective spin Hall angle in BiSb (bottom)/FM with in-plane magnetization deposited by magnetron sputtering on sapphire substrates. We showed that inserting an interfacial layer with optimized thickness helps improve the effective spin Hall angle. We achieved a relatively high effective spin Hall angle of 1.7 in BiSb (bottom)/Ru 1 nm/Co 1 nm/Pt 1 nm structure.