Charge-Induced Artifacts in Nonlocal Spin-Transport Measurements: How to Prevent Spurious Voltage Signals
Charge-Induced Artifacts in Nonlocal Spin-Transport Measurements: How to Prevent Spurious Voltage Signals
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DOI：
10.1103/physrevapplied.18.014028
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发表时间：
2021-12
影响因子：
4.6
通讯作者：
F. Volmer;T. Bisswanger;A. Schmidt;C. Stampfer;B. Beschoten
中科院分区：
文献类型：
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作者：
F. Volmer;T. Bisswanger;A. Schmidt;C. Stampfer;B. Beschoten
为了进行自旋敏感的输运测量，通常使用非局域器件几何结构来避免由电荷的漂移引起的寄生电压。然而，在绝大多数报告的非本地自旋阀，汉勒自旋进动，或自旋霍尔测量的背景信号已被观察到，是不相关的自旋。我们讨论了七种不同类型的这些电荷诱导信号，并解释了这些文物如何可能导致错误或误导性的结论时，错误地归因于自旋输运。电荷驱动信号可分为两组：器件结构和/或测量设置固有的信号以及取决于共模电压的信号。我们设计并构建了一个压控电流源，通过在非本地检测电路中创建虚拟接地，显著减少了DC和AC测量中后一组的所有杂散电压信号。这对于基于锁定的测量技术尤其重要，其中共模电压可以产生相移的频率依赖信号，其幅度比实际自旋信号大几个数量级。在石墨烯基非局域自旋阀器件上进行的测量表明，由共模电压引起的所有寄生电压信号如何能够被这样的电流源完全抑制。
To conduct spin-sensitive transport measurements, a non-local device geometry is often used to avoid spurious voltages that are caused by the flow of charges. However, in the vast majority of reported non-local spin valve, Hanle spin precession, or spin Hall measurements background signals have been observed that are not related to spins. We discuss seven different types of these charge-induced signals and explain how these artifacts can result in erroneous or misleading conclusions when falsely attributed to spin transport. The charge-driven signals can be divided into two groups: Signals that are inherent to the device structure and/or the measurement setup and signals that depend on a common-mode voltage. We designed and built a voltage-controlled current source that significantly diminishes all spurious voltage signals of the latter group in both DC and AC measurements by creating a virtual ground within the non-local detection circuit. This is especially important for lock-in-based measurement techniques, where a common-mode voltage can create a phase-shifted, frequency-dependent signal with an amplitude several orders of magnitude larger than the actual spin signal. Measurements performed on graphene-based non-local spin valve devices demonstrate how all spurious voltage signals that are caused by a common-mode voltage can be completely suppressed by such a current source.