Polarity Manipulation of Anomalous Hall Effect and Enhanced Spin-Orbit Torques in Perpendicular Synthetic Antiferromagnets

Zhang, Jingying; Xue, Hongwei; Li, Ziyang; Song, Yiwen; Zhang, Jiali; Jiang, Zhiyao; Jin, Qingyuan; Zhang, Zongzhi

doi:10.1103/physrevapplied.20.024063

Cited by 1 publication

(1 citation statement)

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“…Numerous studies have focused on improving ξ SH by identifying new NM layer materials with high spin Hall angles, including the topological insulators (Bi–Se and Bi–Sb) and transition-metal dichalcogenides (WTe 2 , ), which are considered alternatives to traditional heavy metal materials. In addition to the spin source layer, the SOT efficiency is also heavily dependent on the material composition and thickness of the FM layer, as well as the interfacial details. − Achieving full absorption of the injected spin current into the FM layer requires negligible spin memory loss and reduced spin backflow at the NM/FM interface. For instance, significant variations in the spin Hall angle of Pt have been reported under different Pt/FM interfaces, which highlighted the impact of precise interface engineering on improving spin transparency and, consequently, SOT efficiency .…”

Section: Introductionmentioning

confidence: 99%

Enhanced Spin–Orbit Torque Efficiency by the Insertion of a Thin NiO Underlayer in Pt/Co/Ta Films

Zhang,

Jiang,

et al. 2024

ACS Appl. Electron. Mater.

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In this study, significant modulations of perpendicular magnetic anisotropy, spin–orbit torque (SOT) efficiency (ξSH), and magnetic damping have been achieved in Pt/Co/Ta films after inserting an insulating NiO underlayer. As the NiO thickness (t NiO) varies from 0 to 2 nm, ξSH exhibits a nonmonotonic variation trend, initially increasing and then decreasing after reaching a maximum value at t NiO = 1 nm. The maximum SOT efficiency is as high as 0.60, nearly twice as large as that in the sample without NiO. Based on the NiO thickness dependencies of effective perpendicular anisotropy field and magnetic damping factor, we can conclude that the complex variation in ξSH is attributable to the combined effects of modified interfacial orbital hybridization and spin absorption by the NiO layer. Significantly, the latter is identified as the primary enhancement mechanism at t NiO < 1 nm, as it prevents spins with adverse polarization from reflecting back to the magnetic layer. Our findings demonstrate an alternative approach toward high SOT efficiency by engineering heterostructures with a magnetic insulator underlayer, which may play a powerful role in developing advanced energy-efficient spintronic devices.

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