The spin Nernst effect in tungsten

Sheng, Peng; Sakuraba, Yuya; Lau, Yong‐Chang; Takahashi, Saburo; Mitani, Seiji; Hayashi, Masamitsu

doi:10.1126/sciadv.1701503

Cited by 118 publications

(78 citation statements)

References 64 publications

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“…A further increase in the W thickness leads to a slight linear enhancement in the magnitude of the effective fields induced by the current. Thus, the sharp increase in the SOT efficiency is completed when tW is comparable to the spin diffusion length, which for W lies in the range from 1.1 to 3.5 nm [24,27]. Experimental samples based on Ru/Co/Ru films were prepared by magnetron sputtering on an oxidized SiO2 silicon substrate.…”

Section: Methodsmentioning

confidence: 99%

Advanced Method for the Reliable Estimation of Spin-Orbit-Torque Efficiency in Low-Coercivity Ferromagnetic Multilayers

et al. 2019

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An experimental study of current-induced magnetization reversal of the Ru/Co/Ru and Ru/Co/Ru/W structures was carried out. In the considered structures, due to the small value of the coercive force comparable in magnitude to the Oersted field and the SOT effect field, magnetization reversal is carried out by moving a domain wall parallel to the direction of current injection. For such a case, a new method for estimating the effective field of SOT based on the analysis of the domain wall position taking into account the distribution of the Oersted field was proposed. This method allowed determining the effective longitudinal field / = 1.6 • 10 −11 / −2 and the efficiency of SOT = 0.03 in the quasi-symmetric Ru/Co/Ru structure. It was found that adding the W capping layer enhances the SOT effect by 5 times. I.

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Section: Methodsmentioning

confidence: 99%

Advanced Method for the Reliable Estimation of Spin-Orbit-Torque Efficiency in Low-Coercivity Ferromagnetic Multilayers

et al. 2019

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“…This thermally driven spin transport phenomenon in nonmagnetic materials is called the spin Nernst effect (SNE) [13]. It has * gyguo@phys.ntu.edu.tw already been experimentally observed in several materials such as Pt thin film [14] and tungsten [15]. This would make the spintronic devices powered by heat (known as spin caloritronics) possible.…”

Section: Introductionmentioning

confidence: 99%

Tunable large spin Hall and spin Nernst effects in the Dirac semimetals ZrXY (X=Si,Ge;Y=S,Se,Te)
Yen
¹
,
Guo
²

2020
Phys. Rev. B
37
2
26
0
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The ZrSiS-type compounds are Dirac semimetals and thus have been attracting considerable interest in recent years due to their topological electronic properties and possible technological applications. In particular, gapped Dirac nodes can possess large spin Berry curvatures and thus give rise to large spin Hall effect (SHE) and spin Nernst effect (SNE), which may be used to generate pure spin current for spintronics and spin caloritronics without applied magnetic field or magnetic material. In this paper we study both SHE and SNE in ZrXY (X = Si, Ge; Y = S, Se, Te) based on ab initio relativistic band structure calculations. Our theoretical calculations reveal that some of these compounds exhibit large intrinsic spin Hall conductivity (SHC) and spin Nernst conductivity (SNC). For example, the calculated SHC of ZrSiTe is as large as -755 ( /e)(S/cm). Since the electric conductivity of these Dirac semimetals are much smaller than that of platinum which has the largest intrinsic SHC of ∼2200 ( /e)(S/cm), this indicates that they will have a larger spin Hall angle (and hence a more efficient charge-spin current conversion) than that of platinum. Remarkably, we find that both the magnitude and sign of the SHE and SNE in these compounds can be significantly tuned by changing either the electric field direction or spin current direction and may also be optimized by slightly varying the Fermi level via chemical doping. Analysis of the calculated band-and k-resolved spin Berry curvatures show that the large SHE and SNE as well as their remarkable tunabilities originate from the presence of many slightly spin-orbit coupling-gapped Dirac nodal lines near the Fermi level in these Dirac semimetals. Our findings thus suggest that the ZrSiS-type compounds are promising candidates for spintronic and spin caloritronic devices, and will certainly stimulate further experiments on these Dirac semimetals.

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“…The interplay of the spin Hall effect (SHE) and the ISHE induces an anisotropic electric resistance in the conductor depending on the relative orientation between the spin polarization of the normal metal and the magnetization of the magnetic insulator. Whereas the SMR uses an electric potential to inject the charge current, the so-called spin Nernst magnetothermopower is driven by an in-plane thermal gradient and can be described by the recently discovered spin Nernst effect3132 in combination with the ISHE. Hints of these effects were already observed as side-effects in experiments using heatable electric contact tips26.…”

mentioning

confidence: 99%

Quantitative separation of the anisotropic magnetothermopower and planar Nernst effect by the rotation of an in-plane thermal gradient

Reimer

Meier

Bovender

et al. 2017

Sci Rep

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A thermal gradient as the driving force for spin currents plays a key role in spin caloritronics. In this field the spin Seebeck effect (SSE) is of major interest and was investigated in terms of in-plane thermal gradients inducing perpendicular spin currents (transverse SSE) and out-of-plane thermal gradients generating parallel spin currents (longitudinal SSE). Up to now all spincaloric experiments employ a spatially fixed thermal gradient. Thus, anisotropic measurements with respect to well defined crystallographic directions were not possible. Here we introduce a new experiment that allows not only the in-plane rotation of the external magnetic field, but also the rotation of an in-plane thermal gradient controlled by optical temperature detection. As a consequence, the anisotropic magnetothermopower and the planar Nernst effect in a permalloy thin film can be measured simultaneously. Thus, the angular dependence of the magnetothermopower with respect to the magnetization direction reveals a phase shift, that allows the quantitative separation of the thermopower, the anisotropic magnetothermopower and the planar Nernst effect.Adding the spin degree of freedom to conventional charge-based electronics opens the field of spintronics 1,2 with promising advantages such as decreased electric power consumption and increased integration densities. While spinelectronics use only voltages as driving force for currents, thermal gradients and the interaction between spins and heat currents have already been shown to provide new effects. Spin caloritronics investigate these interactions and promotes the search for applications such as heat sensors or waste heat recyclers 3,4 , that can improve thermoelectric devices.One of the most important and well established phenomena in spin caloritronics is the longitudinal spin Seebeck effect (LSSE) [5][6][7][8][9][10][11] , which uses typically out-of-plane thermal gradients in magnetic thin films for the generation of a spin current parallel to the thermal gradient. This pure spin current is then injected into an adjacent non-magnetic conductor with high spin-orbit coupling, e.g. Pt, which transforms the spin current into an electric voltage via the inverse spin Hall effect (ISHE). In very recent investigations, the LSSE was even detected without any Pt and ISHE by the use of the anomalous Hall effect in Au 12 and by time-resolved magnetooptic Kerr effect in Au and Cu 13 . Besides the application of an out-of-plane thermal gradient, effects driven by in-plane thermal gradients were also investigated. The transverse spin Seebeck effect (TSSE), the spin current generation perpendicular to an in-plane thermal gradient, was reported for metals 14 , semiconductors 15 and insulators 16 . However, it has been noted that TSSE experiments in metals and semiconductors can be influenced by parasitic effects like the planar

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The spin Nernst effect in tungsten

Abstract: The spin Nernst effect, direct conversion of heat current to spin current, is observed in W/CoFeB/MgO heterostructures.

Cited by 118 publications

References 64 publications

Advanced Method for the Reliable Estimation of Spin-Orbit-Torque Efficiency in Low-Coercivity Ferromagnetic Multilayers

Advanced Method for the Reliable Estimation of Spin-Orbit-Torque Efficiency in Low-Coercivity Ferromagnetic Multilayers

Tunable large spin Hall and spin Nernst effects in the Dirac semimetals ZrXY (X=Si,Ge;Y=S,Se,Te)
Yen
¹
,
Guo
²

2020
Phys. Rev. B
37
2
26
0
View full text Add to dashboard Cite

Quantitative separation of the anisotropic magnetothermopower and planar Nernst effect by the rotation of an in-plane thermal gradient

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The spin Nernst effect in tungsten

Abstract: The spin Nernst effect, direct conversion of heat current to spin current, is observed in W/CoFeB/MgO heterostructures.

Cited by 118 publications

References 64 publications

Advanced Method for the Reliable Estimation of Spin-Orbit-Torque Efficiency in Low-Coercivity Ferromagnetic Multilayers

Advanced Method for the Reliable Estimation of Spin-Orbit-Torque Efficiency in Low-Coercivity Ferromagnetic Multilayers

Tunable large spin Hall and spin Nernst effects in the Dirac semimetals ZrXY (X=Si,Ge;Y=S,Se,Te)Yen1, Guo2 2020Phys. Rev. B372260View full textAdd to dashboardCite

Quantitative separation of the anisotropic magnetothermopower and planar Nernst effect by the rotation of an in-plane thermal gradient

Contact Info

Product

Resources

About

Tunable large spin Hall and spin Nernst effects in the Dirac semimetals ZrXY (X=Si,Ge;Y=S,Se,Te)
Yen
¹
,
Guo
²

2020
Phys. Rev. B
37
2
26
0
View full text Add to dashboard Cite