Here, we have investigated the spin pumping effect of Y3Fe5O12 (YIG)/Cu (tCu nm)/Cr heterostructures at room temperature with the thickness of the Cu interlayer varying from 0.4 nm to 5.0 nm. A huge charge signal Ic = 0.239 μA is observed in a YIG/Cr bilayer with direct contact, whereas Ic drops dramatically by two orders of magnitude when thin Cu interlayers down to 0.4 nm are inserted between YIG and Cr. Meanwhile, the injected spin current Js stays almost invariant for all the heterostructures. The effective spin Hall angle “θSH” of the YIG/Cr interface is found to be three orders of magnitude larger than the spin Hall angle θSH of the bulk Cr layer in YIG/Cu/Cr. The huge spin-charge conversion efficiency at the YIG/Cr interface is attributed to the inverse Rashba–Edelstein effect. Our experimental results demonstrate the dominant role of the interfacial effect in the spin-charge conversion process of the YIG/Cr heterostructures.

中文翻译：

---

YIG/Cr异质结构中强界面诱导的自旋电荷转换

在这里，我们研究了室温下 Y3Fe5O12 (YIG)/Cu (tCu nm)/Cr 异质结构的自旋泵浦效应，其中 Cu 夹层的厚度从 0.4 nm 到 5.0 nm。在直接接触的 YIG/Cr 双层中观察到巨大的电荷信号 Ic = 0.239 μA，而当在 YIG 和 Cr 之间插入低至 0.4 nm 的薄 Cu 夹层时， Ic 急剧下降两个数量级。同时，注入的自旋电流 Js 对于所有异质结构几乎保持不变。发现 YIG/Cr 界面的有效自旋霍尔角“θSH”比 YIG/Cu/Cr 中体 Cr 层的自旋霍尔角 θSH 大三个数量级。YIG/Cr 界面处巨大的自旋电荷转换效率归因于反 Rashba-Edelstein 效应。