Enhanced spin–orbit torque efficiency with low resistivity in perpendicularly magnetized heterostructures consisting of Si-alloyed β-W layers

Kim, Tae Hyun; Nguyen, Trong; Kim, Gyu Won; Lee, Minhyeok; Yoon, Seok In; Rhim, H. Sonny; Kim, Young Keun

doi:10.1016/j.apsusc.2022.155352

Cited by 6 publications

(2 citation statements)

References 48 publications

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“…[24,25] All these materials have polycrystalline (textured) or single-crystal structures, in which a large spin Hall effect is theoretically expected by an intrinsic mechanism based on the band structure of materials with long-range crystal order [26][27][28][29] . As a result of extensive experimental studies, some such materials exhibiting large spin Hall angles have been observed, and with these j c0 < 1 × 10 7 A cm −2 could be achieved [30][31][32][33][34][35] . The second essential requirement is the high annealing stability of the spin Hall material.…”

Section: Introductionmentioning

confidence: 99%

Highly Energy‐Efficient Spin‐Orbit‐Torque Magnetoresistive Memory with Amorphous W─Ta─B Alloys

Hibino,

Yamamoto,

Yakushiji

et al. 2023

Adv Elect Materials

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The spin Hall effect enables fast and reliable writing operations for next‐generation spin‐orbit‐torque magnetoresistive random‐access memories (SOT‐MRAMs). To develop SOT‐MRAMs; however, the spin Hall material should have a sufficiently low writing energy and high annealing stability for the semiconductor integration process. Thus far, none of the crystalline‐based spin Hall materials are able to satisfy these requirements. Here, a promising solution for SOT‐MRAMs is provided using amorphous W─Ta─B alloys. Even without a long‐range crystal order, W─Ta─B alloys exhibit both large effective spin Hall angles up to 40% derived from a Ta substitutional doping and superior annealing stability (up to 400 °C) due to the addition of B, enabling them to satisfy both requirements. Nanoscale three‐terminal SOT‐MRAM cells are fabricated, and these are demonstrated to have high magnetoresistance ratios (up to 130%) and extremely low intrinsic switching current densities (down to 4 × 106 A cm−2). These results show that amorphous spin Hall materials can provide the key for realizing high‐performance SOT‐MRAMs.

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Section: Introductionmentioning

confidence: 99%

Highly Energy‐Efficient Spin‐Orbit‐Torque Magnetoresistive Memory with Amorphous W─Ta─B Alloys

Hibino,

Yamamoto,

Yakushiji

et al. 2023

Adv Elect Materials

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show abstract

“…Tremendous effort has been devoted to enhancing the charge-spin conversion efficiency in HM/FM bilayers, either by exploiting novel spin source materials with larger spin Hall angles or by modifying the HM/FM interface to enhance the spin transport efficiency. − Recently, different kinds of two-dimensional materials (MoS 2 , WTe 2 , Fe 3 GeTe 2 , and Fe 4 GeTe 2 ) and topological insulators (Bi 0.9 Sb 0.1 and Bi 2 Sb 3 ) have been investigated due to a larger spin Hall angle and potentially lower switching current density. However, the complex processing and preparation are not conducive to the massive production of SOT spintronic devices. ,− Moreover, voltage-controlled magnetic anisotropy (VCMA) has been proposed as an alternative approach to reducing the SOT switching current.…”

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confidence: 99%

Heat-Assisted Magnetization Switching in Flexible Spin–Orbit Torque Devices

Wang,

Liu,

et al. 2024

Nano Lett.

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Heat-assisted magnetic anisotropy engineering has been successfully used in selective magnetic writing and microwave amplification due to a large interfacial thermal resistance between the MgO barrier and the adjacent ferromagnetic layers. However, in spin−orbit torque devices, the writing current does not flow through the tunnel barrier, resulting in a negligible heating effect due to efficient heat dissipation. Here, we report a dramatically reduced switching current density of ∼2.59 MA/cm 2 in flexible spin−orbit torque heterostructures, indicating a 98% decrease in writing energy consumption compared with that on a silicon substrate. The reduced driving current density is enabled by the dramatically decreased magnetic anisotropy due to Joule dissipation and the lower thermal conductivity of the flexible substrate. The large magnetic anisotropy could be fully recovered after the impulse, indicating retained high stability. These results pave the way for flexible spintronics with the otherwise incompatible advantages of low power consumption and high stability.

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Optical Verification of Physically Unclonable Function Devices Based on Spin‐Orbit Torque Switching

Lee

Yoon

et al. 2023

Adv Elect Materials

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Physically unclonable functions (PUFs) are used for various applications such as anticounterfeiting, authentication, and secret key generation. They are generally evaluated through electrical measurements, requiring much time and effort due to the many electrical connections required. This study proposes an optical verification of spin‐orbit torque (SOT) devices for PUF design. SOT devices have gained much attention because they resist degradation and thermal changes and can generate secret keys with high reproducibility. A simple optical method based on the magneto‐optical Kerr effect is introduced to verify the authenticity of the proposed SOT PUF device. Furthermore, this study assesses the feasibility of using a W/CoFeB/MgO/Ta structure as a PUF. The 24‐bit device shows a reliability of 97.8 ± 1.03%, making it a promising candidate for use as a spintronics‐based PUFs.

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Enhanced spin–orbit torque efficiency with low resistivity in perpendicularly magnetized heterostructures consisting of Si-alloyed β-W layers

Cited by 6 publications

References 48 publications

Highly Energy‐Efficient Spin‐Orbit‐Torque Magnetoresistive Memory with Amorphous W─Ta─B Alloys

Highly Energy‐Efficient Spin‐Orbit‐Torque Magnetoresistive Memory with Amorphous W─Ta─B Alloys

Heat-Assisted Magnetization Switching in Flexible Spin–Orbit Torque Devices

Optical Verification of Physically Unclonable Function Devices Based on Spin‐Orbit Torque Switching

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