Current-induced out-of-plane torques in a single permalloy layer with lateral structural asymmetry

Aoki, Motomi; Shigematsu, Ei; Ohshima, Ryo; Shinjo, Teruya; Shiraishi, Masashi; Ando, Yoshinori

doi:10.1103/physrevb.105.144407

Cited by 6 publications

(5 citation statements)

References 50 publications

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“…The conventional SOT efficiency for the current along the a axis normalξSOTa−axis) and the b axis (normalξSOTb−axis) is about 0.05 and 0.28, respectively. At the same time, we get the unconventional SOT efficiency for the current along the a axis, which can be calculated as ( 47 , 50 )normalξZ,FL=S0A1⋅normaleℏ⋅normalμ0MStFMtNM⋅1+4πMnormaleffHext…”

Section: Resultsmentioning

confidence: 99%

“…It is known that the unconventional field-like SOT can also be caused by the Oersted field ( 51 ), which usually shows a frequency dependence ( 50 ). Therefore, we plot | S 0 / A 1 | (corresponding to the unconventional field-like SOT) and | A 0 / A 1 | (corresponding to the unconventional damping-like SOT) as a function of microwave frequencies in fig.…”

Section: Resultsmentioning

confidence: 99%

“…Therefore, we plot | S 0 / A 1 | (corresponding to the unconventional field-like SOT) and | A 0 / A 1 | (corresponding to the unconventional damping-like SOT) as a function of microwave frequencies in fig. S4 ( 50 ). As shown in fig.…”

Section: Resultsmentioning

confidence: 99%

“…(50). As shown in fig.S4A, |S 0 /A 1 | does not show a pronounced change as a function of microwave frequency for the current along the a axis, which can exclude the influence of the Oersted field caused by microwave current.…”

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confidence: 90%

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Room temperature field-free switching of perpendicular magnetization through spin-orbit torque originating from low-symmetry type II Weyl semimetal

Zhang,

Xu,

Jia

et al. 2023

Sci. Adv.

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Spin-orbit torque (SOT) is a promising strategy to deterministically switch the perpendicular magnetization, but usually requires an in-plane magnetic field for breaking the mirror symmetry, which is not suitable for most advanced industrial applications. Van der Waals (vdW) materials with low crystalline symmetry and topological band structures, e.g., Weyl semimetals (WSMs), potentially serve as an outstanding system that may simultaneously realize field-free switching and high energy efficiency. Yet, the demonstration of these superiorities at room temperature has not been realized. Here, we achieve a field-free switching of perpendicular magnetization by using a layered type II WSM, TaIrTe 4 , in a TaIrTe 4 /Ti/CoFeB system at room temperature with the critical switching current density ~2.4 × 10 6 A cm −2 . The field-free switching is ascribed to the out-of-plane SOT allowed by the low crystal symmetry. Our work suggests that using low-symmetry materials to generate SOT is a promising route for the manipulation of perpendicular magnetization at room temperature.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 90%

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Room temperature field-free switching of perpendicular magnetization through spin-orbit torque originating from low-symmetry type II Weyl semimetal

Zhang,

Xu,

Jia

et al. 2023

Sci. Adv.

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“…A [23]). and symmetric (S) component in the ST-FMR spectrum, where M is the magnetization vector [25,26]. Under the experimental setup shown in Fig.…”

Section: ⅱ Experimental Proceduresmentioning

confidence: 99%

Anomalous sign inversion of spin-orbit torque in ferromagnetic/nonmagnetic bilayer systems due to self-induced spin-orbit torque

et al. 2022

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Self-induced spin-orbit torques (SI-SOTs) in ferromagnetic (FM) layers have been overlooked when estimating the spin Hall angle (SHA) of adjacent nonmagnetic (NM) layers. In this work, we observe anomalous sign inversion of the total SOT in the spin-torque ferromagnetic resonance due to the enhanced SI-SOT, and successfully rationalize the sign inversion through a theoretical calculation considering the SHE in both the NM and FM layers. The findings show that using an FM layer whose SHA sign is the same as that of the NM achieves efficient SOT-magnetization switching with the assistance of the SI-SOT. The contribution of the SI-SOT becomes salient for a weakly conductive NM layer, and conventional analyses that do not consider the SI-SOT can overestimate the SHA of the NM layer by a factor of more than 150.

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Spin current and spin-orbit torque induced by ferromagnets

Kim,

Park,

Lee

2024

npj Spintronics

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Spin torque is typically classified based on how the spin current is generated and injected into a magnet for manipulation. Spin-orbit torque arises from the spin-orbit interaction in a nearby normal metal, while spin-transfer torque results from exchange interactions in another ferromagnet. Recent studies have suggested that a ferromagnet itself can also generate a spin current through spin-orbit coupling, leading to the emergence of ferromagnet-induced spin-orbit torque as another class of spin torque. This novel torque mechanism not only inherits the advantages of spin-orbit torque architectures, such as separate reading and writing paths in memory applications but also offers the flexibility to control the generated spin direction by manipulating the orientation of the ferromagnet responsible for generating the spin current. In this article, we review the phenomena related to spin currents generated by ferromagnets, explore their physical descriptions in heterostructures, and discuss several spin torque architectures based on this effect. Ferromagnet-induced spin-orbit torque not only introduces new physical consequences by combining spin-orbit and exchange interactions but also offers a promising building block in spintronics with significant potential for diverse applications.

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Current-induced out-of-plane torques in a single permalloy layer with lateral structural asymmetry

Cited by 6 publications

References 50 publications

Room temperature field-free switching of perpendicular magnetization through spin-orbit torque originating from low-symmetry type II Weyl semimetal

Room temperature field-free switching of perpendicular magnetization through spin-orbit torque originating from low-symmetry type II Weyl semimetal

Anomalous sign inversion of spin-orbit torque in ferromagnetic/nonmagnetic bilayer systems due to self-induced spin-orbit torque

Spin current and spin-orbit torque induced by ferromagnets

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