The accuracy of measurements in Amplitude Modulation Atomic Force Microscopy (AFM) is directly related to the geometry of the tip. The AFM tip is characterized by its radius of curvature, which could suffer from alterations due to repetitive mechanical contact with the surface. An estimation of the tip change would allow the user to assess the quality during imaging. In this work, we introduce a method for tip radius evaluation based on the nonlinear dynamic response of the AFM cantilever. A nonlinear fitting procedure is used to match several curves with softening nonlinearity in the noncontact regime. By performing measurements in this regime, we are able to maximize the influence of the tip radius on the AFM probe response, and this can be exploited to estimate with good accuracy the AFM tip radius.

中文翻译：

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用于估计原子力显微镜中尖端半径的非线性动力学

调幅原子力显微镜 (AFM) 中测量的准确性与尖端的几何形状直接相关。AFM 尖端的特点是其曲率半径，由于与表面重复机械接触，曲率半径可能会发生变化。尖端变化的估计将允许用户在成像期间评估质量。在这项工作中，我们介绍了一种基于 AFM 悬臂非线性动态响应的尖端半径评估方法。非线性拟合程序用于在非接触状态下匹配具有软化非线性的多条曲线。通过在这种情况下进行测量，我们能够最大限度地提高尖端半径对 AFM 探针响应的影响，并且可以利用这一点来准确地估计 AFM 尖端半径。