Substantial enhancement of thermal spin polarization in Py/Cu interface

Hu, Shaojie; Jing-yan, Zhao; Wang, Lei; Cui, Xiaomin; Ohnishi, Kohei; Ariki, Taisei; Min, Tai; Xia, Ke; Kimura, Takashi

doi:10.1103/physrevmaterials.2.104403

Cited by 5 publications

(6 citation statements)

References 46 publications

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“…However, we did not observe a thermal spin signal in configuration of Py/Cu/CFA even an AC bias current of 4.3 mA, as shown in figure 6(b). This can be understood by considering the low spin-dependent Seebeck coefficient of Py at room temperature [39]. We can also see that the base values of the thermal spin curves are much lower for both measurement configurations.…”

Section: Resultsmentioning

confidence: 72%

“…Here, we assume that the spin diffusion length of CoFeAl and Py are λ CoFeAl = 2 nm and λ Py = 2 nm at 295 K. Because the electron spin relaxations in the Py, CFA, and Cu are dominated by the Elliott-Yafet mechanism, we can assume the product of spin diffusion length and resistivity is constant for them [37,38]. The products of spin diffusion length and resistivity are γ CFA = λ CFA × ρ CFA = 0.9 fΩ • m 2 , γ Py = λ Py × ρ Py = 0.71 fΩ • m 2 and γ Cu = λ Cu × ρ Cu = 13.28 fΩ • m 2 , respectively [23,39]. By fitting the interval distance dependence of the spin signals in figure 2(c) using equation (1), we estimated the spin polarizations of CFA as 0.62 and 0.82 at 295 K and 35 K. For Py, the spin polarizations are 0.35 and To further understand the spin transport properties in the confined spin channel, we also evaluated the temperature dependence of the spin signals.…”

Section: Resultsmentioning

confidence: 99%

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Enhanced spin accumulation in nano-pillar-based lateral spin valve using spin reservoir effect

Cui¹,

Hu²,

Kimura³

2022

J. Phys. D: Appl. Phys.

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Lateral spin valves are ideal nanostructures for investigating spin-transport physics phenomena and promoting the development of future spintronic devices owing to dissipation-less pure spin current. The magnitude of the spin accumulation signal is well understood as a barometer for characterizing spin current devices. Here, we develop a novel fabrication method for lateral spin valves based on ferromagnetic nanopillar structures using a multi-angle deposition technique. We demonstrate that the spin-accumulation signal is effectively enhanced by reducing the lateral dimension of the nonmagnetic spin channel. The obtained results can be quantitatively explained by the confinement of the spin reservoir by considering spin diffusion into the leads. The temperature dependence of the spin accumulation signal and the influence of the thermal spin injection under a high bias current are also discussed.

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Section: Resultsmentioning

confidence: 72%

Section: Resultsmentioning

confidence: 99%

Enhanced spin accumulation in nano-pillar-based lateral spin valve using spin reservoir effect

Cui¹,

Hu²,

Kimura³

2022

J. Phys. D: Appl. Phys.

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“…which the contributions from up-spin and down-spin cancel out each other. [55,56] Owing to the relatively small S xx , S ↑ , and S ↓ represent the similar temperature dependence of S xy with accompanying the sign reversal. The underlying physical mechanism responsible for the observed sign reversal of the ANE voltage is intricately linked to the temperature-induced variations in the spin-dependent Seebeck effect.…”

Section: Figure 5amentioning

confidence: 95%

Efficient Thermo‐Spin Conversion in van der Waals Ferromagnet FeGaTe

Liu,

Hu,

Cui

et al. 2023

Advanced Materials

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Recent discovery of 2D van der Waals magnetic materials has spurred progress in developing advanced spintronic devices. A central challenge lies in enhancing the spin‐conversion efficiency for building spin‐logic or spin‐memory devices. Here, the anomalous Hall and Nernst effects are systematically investigated to uncover significant spin‐conversion effects in above‐room‐temperature van der Waals ferromagnet FeGaTe with perpendicular magnetic anisotropy. The anomalous Hall effect demonstrates an efficient electric spin‐charge conversion with a notable spin Hall angle of over 6%. In addition, the anomalous Nernst effect produces a significant transverse voltage at room temperature without a magnetic field, displaying unique temperature dependence with a maximum transverse Seebeck coefficient of 440 nV K−1 and a Nernst angle of ≈62%. Such an innovative thermoelectric signal arises from the efficient thermo‐spin conversion effect, where the up‐spin and down‐spin electrons move in opposite directions under a temperature gradient. The present study highlights the potential of FeGaTe to enhance thermoelectric devices through efficient thermo‐spin conversion without the need for a magnetic field.

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“…Thermal gradients at the crucial ferromagnet/non-magnetic metal interface can also drive spin injection in the structure in what is often termed the spin-dependent Seebeck effect (SDSE). [30][31][32][33][34][35][36][37][38][39] The dramatic consequences of the interaction of heat and spin place NLSVs firmly in the growing field of spin caloritronics [40][41][42] that examines coupling between heat and spin in materials and devices.…”

Section: Introductionmentioning

confidence: 99%

Thermal gradients and anomalous Nernst effects in membrane-supported nonlocal spin valves

2019

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Metallic non-local spin valves (NLSVs) are important in modern spintronics due to their ability to separate pure spin current from charge current. These metallic nanostructures, often constructed from features with widths in the deep sub-micron regime, generate significant thermal gradients in operation, and the heat generated has important consequences for spin injection and transport. We use e-beam nanolithography to manufacture NLSVs with Ni-Fe alloy ferromagnetic nanowires and aluminum spin channels on 500 nm silicon nitride (Si-N) membranes in order to lower the thermal conductance of the substrate dramatically. While this extreme example of thermal engineering in a spintronic system increases the background non-local signals in ways expected based on earlier work, it also enhances thermoelectric effects, including the anomalous Nernst effect and reveals a previously unknown thermally-assisted electrical spin injection that results from a purely in-plane thermal gradient. We examine these effects as a function of temperature and, by careful comparison with 2D finite element models of the thermal gradients calculated at a single temperature, demonstrate that the anomalous Nernst coefficient of the 35 nm thick Ni-Fe alloy, R N = 0.17 at T = 200 K, is in line with the few previous measurements of this effect for thin films.

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Substantial enhancement of thermal spin polarization in Py/Cu interface

Cited by 5 publications

References 46 publications

Enhanced spin accumulation in nano-pillar-based lateral spin valve using spin reservoir effect

Enhanced spin accumulation in nano-pillar-based lateral spin valve using spin reservoir effect

Efficient Thermo‐Spin Conversion in van der Waals Ferromagnet FeGaTe

Thermal gradients and anomalous Nernst effects in membrane-supported nonlocal spin valves

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