Large spin hall angle enhanced by nitrogen incorporation in Pt films

• Main Authors: Xu, Zhan, Wong, Grayson Dao Hwee, Tang, Jiaxuan, Liu, Er, Gan, Weiliang, Xu, Feng, Lew, Wen Siang
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2022
• Subjects: Science::Physics; Cobalt Compounds; Spin Orbit Coupling
• Online Access: https://hdl.handle.net/10356/161146
• Institution: Nanyang Technological University

We report on the enhancement of spin Hall angle from the CoFeB/Pt interface by introducing nitrogen into the Pt thin film. Spin-torque ferromagnetic resonance measurements on the effective spin Hall angle (θSH) reveal a non-monotonic variation as a function of the amount of nitrogen gas introduced, Q in the film deposition, which peaks at θSH = 0.16 when Q is 8%. Our analysis shows that the θSH enhancement is mainly attributed to the increase in spin-dependent scattering at the interface. The effective magnetic damping decreases with increasing Q due to the reduced spin-orbit coupling. The interfacial spin transparency is also observed to show improvement after the introduction of nitrogen. Moreover, the additional damping-like torque from the interface may also lead to the enhancement of the linewidth modulation.