The method of combining surface acoustic waves (SAWs) with electrical detection has promoted the study of phonon–spin coupling and spintronics. Aiming at problems of difficult detection of DC voltage and unknown origin of spin current caused by SAW in ferromagnetic/light metal systems, we constructed the Ni/Cu/Ta on LiNbO3 substrate and measured acoustic voltages directly, which are used to analyze the spin current induced by SAW. By analyzing the angular dependence of acoustic voltages and estimating the maximum spin current, it is determined that acoustic voltages originate from the acoustic spin–rotation (ASR) coupling and the acoustic spin pumping (ASP) effects. The angular dependence shows that for the longitudinal voltage, the contribution of ASR to ASP is in the ratio of 3.22/3.77, while the transverse voltage is mainly contributed by the ASR. The maximum spin current due to ASR is 0.97 × 105 A/m2, while that due to ASP is 1.47 × 105 A/m2. This work provides ideas for the design of phonon–spin coupled devices.

中文翻译：

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通过声电压检测声自旋-旋转耦合机构产生的自旋电流


将表面声波 （SAW） 与电探测相结合的方法促进了声子-自旋耦合和自旋电子学的研究。针对铁磁/轻金属系统中 SAW 引起的直流电压检测困难和自旋电流来源未知的问题，我们在 LiNbO3 衬底上构建了 Ni/Cu/Ta 并直接测量了声电压，用于分析 SAW 感应的自旋电流。通过分析声电压的角度依赖性并估计最大自旋电流，可以确定声电压来自声自旋-旋转 （ASR） 耦合和声自旋泵浦 （ASP） 效应。角度依赖性表明，对于纵向电压，ASR 对 ASP 的贡献为 3.22/3.77，而横向电压主要由 ASR 贡献。ASR 引起的最大自旋电流为 0.97 × 105 A/m2，而 ASP 引起的最大自旋电流为 1.47 × 105 A/m2。这项工作为声子-自旋耦合器件的设计提供了思路。