We have investigated the spin pumping phenomenon in Fe₈₀Co₂₀/Ta bilayers of different thicknesses in which the ferromagnet grows epitaxially on MgO substrates. We have obtained a Gilbert damping constant for Fe₈₀Co₂₀ as low as α = 1.3(1) 10⁻³, which is smaller than values generally reported in metallic ferromagnets. From the dependence of α with the Fe₈₀Co₂₀ thickness, we extracted the value of the effective spin mixing conductance = 5.7(3) 10¹⁴ cm⁻². Analyzing the Ta and Fe₈₀Co₂₀ thickness dependence of the inverse spin Hall effect voltage, we obtained the transport parameters = 1.1(3) nm and = –0.024(3). We have developed an expression to quantify the efficiency of the spin pumping phenomenon in ferromagnetic/nonmagnetic metal bilayers. The calculated efficiency shows that the Fe₈₀Co₂₀/Ta system is up to an order of magnitude more efficient than other metallic ferromagnetic bilayers reported in the literature.

我们研究了铁磁体在 MgO 衬底上外延生长的不同厚度的Fe ₈₀ Co ₂₀ /Ta 双层中的自旋泵浦现象。我们已经获得了 Fe ₈₀ Co ₂₀的吉尔伯特阻尼常数低至α = 1.3(1) 10 ^-3，该值小于金属铁磁体中通常报道的值。根据α与Fe ₈₀ Co ₂₀厚度的相关性，我们提取了有效自旋混合电导的值= 5.7(3) 10 ¹⁴ cm ^-2。分析 Ta 和 Fe ₈₀ Co ₂₀反自旋霍尔效应电压的厚度依赖性，我们获得了传输参数= 1.1(3) nm 和= –0.024(3)。我们开发了一个表达式来量化铁磁/非磁性金属双层中自旋泵浦现象的效率。计算的效率表明，Fe ₈₀ Co ₂₀ /Ta 系统的效率比文献中报道的其他金属铁磁双层高一个数量级。