Development of new high-frequency nano-spin measurement technique

本研究报告了我们新提出的高频纳米自旋测量技术，即拍场式高频磁力显微镜。通过向CPW提供信号电流并向激励线圈提供参考电流来产生拍频场。信号电流固定在特定GHz范围的频率，而参考被调整以产生具有接近悬臂谐振频率的频率的拍频。由于MFM尖端由拍激励，因此可以成功地在CPW表面上方观察到GHz范围信号频率的磁场梯度。磁场梯度在两个间隙附近最小，但在信号线中心附近最大。这些结果表明，尖端通过拍频场与CPW的RF磁近场密切相互作用，并且探索参考RF场可以以非常高的空间分辨率检测从RF电路组件辐射的RF磁场的分布。

This study reports our newly proposed high-frequency nano-spin measurement technique, that is, beating field typed high-frequency magnetic force microscope. The beating field is produced by supplying a signal current to the CPW and a reference current to an exciting coil. The signal current is fixed at a specific GHz-range frequency, while the reference is adjusted to produce a beat with a frequency near the cantilever resonance frequency. As the MFM tip is excited by the beat, the gradient of magnetic field can be successfully observed above the CPW surface for a GHz-range signal frequency. The gradient of magnetic field is minimized near the two gaps, but is maximized near the center of the signal line. These results demonstrate that the tip interacts closely with the RF magnetic near-field of the CPW through the beating field, and exploring a reference RF field can detect the distribution of RF magnetic fields radiated from a RF circuit component with a very high spatial resolution.