Diamonds to the rescue Keeping track of spin transport inside a spintronic device is challenging. Du et al. came up with a method involving diamond nitrogen-vacancy (NV) centers, which can act like tiny, very sensitive magnetometers. The authors placed diamond nanobeams containing the NV centers in close proximity to the sample. This allowed them to measure the spin chemical potential of spin waves—so-called magnons—with nanometer resolution in the material yttrium iron garnet. Because NV centers are also sensitive to temperature, the method may be of use in spin caloritronics. Science, this issue p. 195 Nanometer spatial resolution measurement is achieved using nitrogen-vacancy centers in diamond. The spin chemical potential characterizes the tendency of spins to diffuse. Probing this quantity could provide insight into materials such as magnetic insulators and spin liquids and aid optimization of spintronic devices. Here we introduce single-spin magnetometry as a generic platform for nonperturbative, nanoscale characterization of spin chemical potentials. We experimentally realize this platform using diamond nitrogen-vacancy centers and use it to investigate magnons in a magnetic insulator, finding that the magnon chemical potential can be controlled by driving the system’s ferromagnetic resonance. We introduce a symmetry-based two-fluid theory describing the underlying magnon processes, measure the local thermomagnonic torque, and illustrate the detection sensitivity using electrically controlled spin injection. Our results pave the way for nanoscale control and imaging of spin transport in mesoscopic systems.

中文翻译：

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磁绝缘体中自旋化学势的控制和局​​部测量

拯救钻石 跟踪自旋电子设备内的自旋传输具有挑战性。杜等人。提出了一种涉及金刚石氮空位 (NV) 中心的方法，它可以像微型、非常灵敏的磁力计一样工作。作者将包含 NV 中心的金刚石纳米束放置在靠近样品的位置。这使他们能够在材料钇铁石榴石中以纳米分辨率测量自旋波（所谓的磁振子）的自旋化学势。由于 NV 中心对温度也很敏感，因此该方法可用于自旋热电子学。科学，这个问题 p。195 纳米空间分辨率测量是使用金刚石中的氮空位中心实现的。自旋化学势表征自旋扩散的趋势。探测这个数量可以提供对磁性绝缘体和自旋液体等材料的深入了解，并有助于优化自旋电子器件。在这里，我们引入单自旋磁力计作为自旋化学势的非微扰纳米级表征的通用平台。我们使用金刚石氮空位中心通过实验实现了这个平台，并用它来研究磁绝缘体中的磁振子，发现可以通过驱动系统的铁磁共振来控制磁振子的化学势。我们介绍了一种基于对称性的双流体理论，描述了潜在的磁振子过程，测量了局部热磁子扭矩，并使用电控自旋注入说明了检测灵敏度。我们的结果为介观系统中自旋输运的纳米级控制和成像铺平了道路。