Electrical switching of perpendicular magnetization in a single ferromagnetic layer

Liu, Liang; Yu, Jeffrey W.; González‐Hernández, Rafael; Li, Changjian; Deng, Jinyu; Lin, Weinan; Zhou, Chang; Zhou, Tiejun; Zhou, Jing; Wang, Han; Guo, Rui; Yoong, Herng Yau; Chow, Gan Moog; Han, Xiufeng; Dupé, Bertrand; Železný, Jakub; Sinova, Jairo; Chen, Jingsheng

doi:10.1103/physrevb.101.220402

Cited by 87 publications

(80 citation statements)

References 28 publications

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“…The novel bulk τ DL we demonstrate here may also provide a possible interpretation for the absence of τ DL in thin L 1 0 ‐FePt single crystal, [ 28 ] the presence of self‐induced switching in very thick L 1 0 ‐FePt single crystal, [ 29 ] and the presence of a nonzero τ DL in Co/Pd multilayer nanowires [ 30 ] and in a 15 nm‐thick nearly compensated ferrimagnetic Tb‐Co film. [ 31 ] However, the existing models involving a long‐range composition gradient [ 29,32,33 ] are clearly irrelevant to the novel bulk τ DL we establish in this work.…”

Section: Resultsmentioning

confidence: 89%

Observation of Strong Bulk Damping‐Like Spin‐Orbit Torque in Chemically Disordered Ferromagnetic Single Layers

Zhu

Zhang

Muller

et al. 2020

Adv Funct Materials

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Strong damping-like spin-orbit torque (τ DL) has great potential for enabling ultrafast energy-efficient magnetic memories, oscillators, and logic. So far, the reported τ DL exerted on a thin-film magnet must result from an externally generated spin current or from an internal non-equilibrium spin polarization in non-centrosymmetric GaMnAs single crystals. Here, for the first time a very strong, unexpected τ DL is demonstrated from current flow within ferromagnetic single layers of chemically disordered, face-centered-cubic CoPt. It is established here that the novel τ DL is a bulk effect, with the strength per unit current density increasing monotonically with the CoPt thickness, and is insensitive to the presence or absence of spin sinks at the CoPt surfaces. This τ DL most likely arises from a net transverse spin polarization associated with a strong spin Hall effect, while there is no detectable long-range asymmetry in the material. These results broaden the scope of spin-orbitronics and provide a novel avenue for developing single-layer-based spin-torque memory, oscillator, and logic technologies.

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Section: Resultsmentioning

confidence: 89%

Observation of Strong Bulk Damping‐Like Spin‐Orbit Torque in Chemically Disordered Ferromagnetic Single Layers

Zhu

Zhang

Muller

et al. 2020

Adv Funct Materials

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“…This coexistence has clearly been shown in the experiments of Das et al [8] and was also found in other recent works. [9][10][11] An SAHE-type spin current in a single magnetic layer cannot produce a spin-torque on its own magnetization because its spin polarization is along the direction of this magnetization. In contrast, the SHE-like spin current inside a single magnetic layer can give rise to a torque on the magnetization of the single layer itself, [6,7] namely, a self-torque.…”

mentioning

confidence: 99%

“…Several experiments have shown clear signs of such torques on single layers, although, in most cases, a specific mechanism could not be clearly identified and characterized. [9][10][11][20][21][22][23][24] In GdFeCo ferrimagnetic alloys, strong spin-orbit interactions are expected from the 5d band introduced by Gd. The presence of large SOC effects is demonstrated by the welldefined Rashba surfaces found on Gd metal.…”

mentioning

confidence: 99%

Current‐Induced Spin Torques on Single GdFeCo Magnetic Layers

et al. 2021

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A novel direction of spintronics, namely "spin-orbitronics", exploits the spin-orbit coupling (SOC) to generate spin currents, which can then induce spin-orbit torques (SOT) to manipulate magnetization. [1] This opens technological applications such as the three-terminal magnetic random memory Spintronics exploit spin-orbit coupling (SOC) to generate spin currents, spin torques, and, in the absence of inversion symmetry, Rashba and Dzyaloshinskii-Moriya interactions. The widely used magnetic materials, based on 3d metals such as Fe and Co, possess a small SOC. To circumvent this shortcoming, the common practice has been to utilize the large SOC of nonmagnetic layers of 5d heavy metals (HMs), such as Pt, to generate spin currents and, in turn, exert spin torques on the magnetic layers. Here, a new class of material architectures is introduced, excluding nonmagnetic 5d HMs, for high-performance spintronics operations. Very strong current-induced torques exerted on single ferrimagnetic GdFeCo layers, due to the combination of large SOC of the Gd 5d states and inversion symmetry breaking mainly engineered by interfaces, are demonstrated. These "self-torques" are enhanced around the magnetization compensation temperature and can be tuned by adjusting the spin absorption outside the GdFeCo layer. In other measurements, the very large emission of spin current from GdFeCo, 80% (20%) of spin anomalous Hall effect (spin Hall effect) symmetry is determined. This material platform opens new perspectives to exert "self-torques" on single magnetic layers as well as to generate spin currents from a magnetic layer.

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“…Identical measurements were carried out in a reference sample with the structure of STO substrate/MnGa (20 nm)/SiO 2 (4 nm), in which no switching phenomenon is observed. This verifies that the switching is not derived from the FM layer itself [37]. With H x = 0.5 × 10 [13,31,32].…”

Section: Science China Materialsmentioning

confidence: 53%

Giant spin torque efficiency in single-crystalline antiferromagnet Mn2Au films

et al. 2021

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Antiferromagnetic (AFM) materials have attracted wide attention in spin-orbit torque (SOT)-based spintronic due to its abundant spin-dependent properties and unique advantage of immunity against external field perturbations. To act as the charge-to-spin conversion source in energy-saving spintronic devices, it is of great importance for the AFM material to possess a large spin torque efficiency (ξ DL). In this work, using the spin torque ferromagnetic resonance (ST-FMR) technique and a Mn 2 Au/NiFe(Py) bilayer system, we systemically study the ξ DL of AFM Mn 2 Au films with different crystal structures. Compared with polycrystalline Mn 2 Au with effective ξ DL < 0.051, we show a much larger ξ DL of~0.333 in single-crystal Mn 2 Au, which arises from the large spin Hall conductivity instead of electrical resistivity. Moreover, with a further contribution of interfacial effects, the effective ξ DL of single-crystalline Mn 2 Au/Py system increases to 0.731, which is more than two times larger than the value of~0.22 reported for the Mn 2 Au/CoFeB system. By utilizing the large ξ DL of Mn 2 Au in a perpendicularly magnetized MnGa/Mn 2 Au system, energy-efficient deterministic magnetization switching with a current density at~10 6 A cm −2 is achieved. Our results reveal a significant potential of Mn 2 Au as an efficient SOT source and shed light on its application in future AFM material-based SOT integration technology.

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Electrical switching of perpendicular magnetization in a single ferromagnetic layer

Cited by 87 publications

References 28 publications

Observation of Strong Bulk Damping‐Like Spin‐Orbit Torque in Chemically Disordered Ferromagnetic Single Layers

Observation of Strong Bulk Damping‐Like Spin‐Orbit Torque in Chemically Disordered Ferromagnetic Single Layers

Current‐Induced Spin Torques on Single GdFeCo Magnetic Layers

Giant spin torque efficiency in single-crystalline antiferromagnet Mn2Au films

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