The Practical Material Challenges Involved in using the Topological Insulator BiSb in a Spin Transfer Device

York, Brian; Hai, Pham Nguyen; Le, Quang Tuan; Hwang, Chul Ju; Nguyen, Khai V.; Ho, H.; Sasaki, J.; Liu, X.; Le, S.; Ho, M.; Takano, H.

doi:10.1109/tmrc53175.2021.9605108

Cited by 4 publications

(1 citation statement)

References 2 publications

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“…BiSb typically crystallizes in a rhombohedral A7 crystal structure with a specific ordered arrangement of Bi and Sb atoms, as shown in Figure a. However, the low melting point of the BiSb alloy raises concerns about Bi/Sb diffusion and phase separation, which could compromise SOT efficiency during annealing and even room-temperature (RT) aging. , Also, the TSS of BiSb thin films was reported to be significantly affected by the selection of adjacent layers. ,− To date, it still remains a critical aspect requiring further investigation of the phenomenon of interdiffusion in the BiSb alloy with neighboring layers and interface chemistry to fully exploit the potential of BiSb-based heterostructures for spintronic applications.…”

Section: Introductionmentioning

confidence: 99%

Spin–Orbit Torque Modulated by Interface Chemistry in Topological BiSb/NiFe Bilayers with Titanium Insertion

Manoj,

Wen,

Uzuhashi

et al. 2024

ACS Appl. Electron. Mater.

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Topological insulators are intriguing materials in the field of spintronics because they exhibit unique electronic properties that hold great promise for device applications. BiSb has attracted more research interest among topological materials due to its remarkably high spin−orbit torque (SOT) efficiency. However, due to the low melting point of the alloy, high diffusivities of Bi/Sb tend to degrade the SOT efficiency with temperature and aging. In this work, we utilize interfacial chemistry driven by a titanium (Ti) spacer between BiSb and NiFe bilayers to improve the SOT efficiency. We investigated the effect of the Ti insertion layer on the SOT efficiency under as-deposited, room-temperature aging, and annealing conditions. The SOT efficiency, estimated from the spin-torque ferromagnetic resonance response, revealed that the samples with the Ti layer had shown a multifold increase in the SOT efficiency compared to those without Ti insertion. Atomic resolution microstructural analyses provided a clear understanding of the interfacial chemistry where Ti successfully hindered the interdiffusion of Ni and Sb. The interfacial chemistry in the vicinity of Ti contributed significantly to the improvement of the SOT efficiency. These results highlight the importance of the Ti insertion layer in the BiSb-based topological material/ferromagnet bilayer systems for SOT applications in spintronics.

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Section: Introductionmentioning

confidence: 99%

Spin–Orbit Torque Modulated by Interface Chemistry in Topological BiSb/NiFe Bilayers with Titanium Insertion

Manoj,

Wen,

Uzuhashi

et al. 2024

ACS Appl. Electron. Mater.

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Nanosecond ultralow power spin orbit torque magnetization switching driven by BiSb topological insulator

Khang

Shirokura

Fan

et al. 2022

Applied Physics Letters

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Topological insulators (TIs) are promising for spin–orbit torque (SOT) switching thanks to their giant spin Hall angle. SOT switching using TIs has been studied so far in the thermal activation regime by direct currents or relatively long pulse currents (≥10 ns). In this work, we studied SOT magnetization switching of (Pt/Co) multilayers with strong perpendicular magnetic anisotropy by the BiSb topological insulator in both thermal activation and fast switching regime with pulse width down to 1 ns. We reveal that the zero-Kelvin threshold switching current density [Formula: see text] is 2.5 × 106 and 4.1 × 106 A/cm2 for the thermal activation regime and fast switching regime in a 800 nm-wide Hall bar device via domain wall depining. From time-resolved measurements using 1 ns pulses, we find that the domain wall velocity is 430–470 m/s at JBiSb = 1.6 × 107–1.7 × 107 A/cm2. Our work demonstrates the potential of the BiSb thin film for ultralow power and fast operation of SOT-based spintronic devices.

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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

et al. 2022

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The Practical Material Challenges Involved in using the Topological Insulator BiSb in a Spin Transfer Device

Cited by 4 publications

References 2 publications

Spin–Orbit Torque Modulated by Interface Chemistry in Topological BiSb/NiFe Bilayers with Titanium Insertion

Spin–Orbit Torque Modulated by Interface Chemistry in Topological BiSb/NiFe Bilayers with Titanium Insertion

Nanosecond ultralow power spin orbit torque magnetization switching driven by BiSb topological insulator

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

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