Magnetic Force Images Using Capacitive Coupling Effect

This chapter focuses on magnetic images taken with the conventional noncontact amplitude modulation (AM) magnetic force microscopy (MFM) frequently picked up topographic features even at larger distances. An MFM method has recently been designed and developed using electrostatic force modulation to separate the magnetic domain structure from the topographic structure on magnetic samples with rough surfaces. In this method, a capacitive coupling is introduced between the tip and the sample using electrostatic force modulation. The chapter introduces an electrostatic force modulation technique and describes the detailed mechanism of the stability improvement through a direct comparison of the traditional bimorph method and the electrostatic force modulation method. The effects on imaging stability of tip–sample separation and perturbations are also investigated. Through this investigation, it will be revealed that the superior performance of the electrostatic force modulation system results from the long-range electrostatic capacitance effect and the direct force modulation effect.