Sensitivity improvement by sample vibration excitation in resistivity measurement for non-magnetic material using MFM

Abstract A method for measuring the sheet resistivity of non-magnetic material by using magnetic force microscopy (MFM) was previously proposed. An approach for enhancing the sensitivity of measuring resistivity using MFM is discussed in this work. While measuring in this method, MFM detects magnetic fields generated by eddy currents induced by the oscillation of a magnetized 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 tip and 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. Around the tip height was smaller than 5 nm, the sensitivity for measuring the resistivity increases to 4–5 times. The use of sample vibration is an effective strategy for high-sensitivity resistivity measurements.