Sensitivity Improvement by Sample Vibration Excitation in Resistivity Measurement for Non-Magnetic Material Using MFM

A novel approach for measuring the electrical resistivity of non-magnetic materials using magnetic force microscopy (MFM) is discussed. In this method, MFM detects magnetic fields generated by eddy currents induced by the oscillation of a magnetized probe tip. To enhance measurement sensitivity, it is essential to increase the magnitude of these eddy currents. It is discussed that introducing controlled sample vibration amplifies eddy current generation by increasing the relative velocity between the probe tip and the sample surface. Theoretical analysis predicts increase of the phase shift by sample vibration, and experimental validation using a modified MFM system confirms the improvement in sensitivity. The calculated and experimental results exhibit relatively good agreement, establishing that sample vibration excitation is an effective strategy for high-sensitivity resistivity measurements.