The spin-current efficiency in ferromagnet (FM)/nonmagnetic metal (NM) heterostructures is a key issue for many subcategories of spintronics, and it is determined by both the spin Hall angle $({\theta }_{\mathrm{SH}})$ of the NM and the spin-mixing conductance $(g_{\uparrow \downarrow })$ related to the constituents and, in particular, to the interface. Here, we study spin transport in the ${\mathrm{Y}}_3{\mathrm{Fe}}_5{\mathrm{O}}_{12}(\mathrm{YIG})$/${\mathrm{W}}_{1\text{−}x}{\mathrm{Cr}}_x$ heterostructure over the full composition by means of the spin Seebeck effect and spin pumping. An appreciably enhanced inverse spin Hall voltage is observed for the substitutional alloy of bcc-$\mathrm{W}$ and $\mathrm{Cr}$, with the maximum obtained at an equiatomic composition. We find that the ${\theta }_{\mathrm{SH}}$ of bcc-${\mathrm{W}}_{0.5}{\mathrm{Cr}}_{0.5}$ is 1.3 times as large as that of β-$\mathrm{W}$, which mainly originates from intensively disordered atomic scattering. More significantly, $\mathrm{YIG}$/bcc-${\mathrm{W}}_{0.5}{\mathrm{Cr}}_{0.5}$ has a $g_{\uparrow \downarrow }$ value of $1.42\times {10}^{18}{\mathrm{m}}^{-2}$, which is more than twice that for $\mathrm{YIG}$/β-$\mathrm{W}$ ($5.98\times {10}^{17}{\mathrm{m}}^{-2}$). Meanwhile, a sizable interfacial electric field is identified in $\mathrm{YIG}$/β-$\mathrm{W}$, but not in $\mathrm{YIG}$/bcc-${\mathrm{W}}_{0.5}{\mathrm{Cr}}_{0.5}$, showing strong correlation between $g_{\uparrow \downarrow }$ and the interfacial electric field. This work not only provides a readily achievable alloy with ${\theta }_{\mathrm{SH}}$ exceeding that of the metastable β-$\mathrm{W}$, but also implies the possibility of manipulating $g_{\uparrow \downarrow }$ via Rashba-type spin-orbit coupling by engineering an interfacial electric field in insulating FM/NM heterostructures.

中文翻译：

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通过体外在散射和界面电场同时增强aY3Fe5O12 / bcc-W1-xCrx异质结构中的自旋霍尔效应和自旋混合电导

铁磁体（FM）/非磁性金属（NM）异质结构中的自旋电流效率是许多自旋电子学子类别的关键问题，它取决于自旋霍尔角 $（{\theta }_{\mathrm{SH}}）$ NM和自旋混合电导 $（G_{\uparrow \downarrow }）$与组成部分有关，尤其是与界面有关。在这里，我们研究自旋${\mathrm{ÿ}}_3{铁}_5{\mathrm{Ø}}_{12}（\mathrm{伊格}）$/${\mathrm{w\; ^}}_{\mathrm{1个}\text{-}X}{铬}_X$通过自旋塞贝克效应和自旋泵浦在整个成分上形成异质结构。对于bcc-的替代合金，观察到逆自旋霍尔电压明显提高。$\mathrm{w\; ^}$ 和 $铬$，在等原子组成下获得的最大值。我们发现${\theta }_{\mathrm{SH}}$ 的密件副本${\mathrm{w\; ^}}_{0.5}{铬}_{0.5}$ 是β-的1.3倍$\mathrm{w\; ^}$，这主要来自强烈无序的原子散射。更重要的是$\mathrm{伊格}$/ bcc-${\mathrm{w\; ^}}_{0.5}{铬}_{0.5}$ 有一个 $G_{\uparrow \downarrow }$ 的价值 $1.42\times {10}^{\mathrm{18岁}}{\mathrm{米}}^{-2}$，是 $\mathrm{伊格}$/β-$\mathrm{w\; ^}$ （$5.98\times {10}^{17}{\mathrm{米}}^{-2}$）。同时，在$\mathrm{伊格}$/β-$\mathrm{w\; ^}$，但不在 $\mathrm{伊格}$/ bcc-${\mathrm{w\; ^}}_{0.5}{铬}_{0.5}$，显示出 $G_{\uparrow \downarrow }$和界面电场。这项工作不仅提供了一种易于实现的合金${\theta }_{\mathrm{SH}}$ 超过亚稳态β-$\mathrm{w\; ^}$，但也暗示有操纵的可能性 $G_{\uparrow \downarrow }$ 通过在绝缘FM / NM异质结构中工程化界面电场来实现Rashba型自旋轨道耦合。