Magnetic domain structure imaging near sample surface with alternating magnetic force microscopy by using AC magnetic field modulated superparamagnetic tip

Abstract

For magnetic domain imaging, with a very high spatial resolution magnetic force microscope, the tip-sample distance should be as small as possible. However, magnetic imaging near the sample surface is very difficult with conventional magnetic force microscopy (MFM) because the interactive forces between the tip and sample include van der Waals and electrostatic forces along with a magnetic force. In this study, we proposed alternating MFM which only extracts a magnetic force near the sample surface without any topographic and electrical crosstalk. In the present method, the magnetization of an FeCo-GdO superparamagnetic tip is modulated by an external AC magnetic field in order to measure the magnetic domain structure without any perturbation from the other forces near the sample surface. Moreover, it is demonstrated that the proposed method can also measure the strength and identify the polarities of the second derivative of the perpendicular stray field from a thin film permanent magnet with a DC demagnetized state and remanent state.

Indirect magnetic force microscopy

“…22 ID-MFM may offer an easier and more versatile approach to keep samples in a fluid environment. Further advances in the design of microfluidic platforms as well as MFM probes 35,36 would be required to enhance the capabilities of ID-MFM.…”

Accurate determination of MFM tip’s magnetic parameters on nanoparticles by decoupling the influence of electrostatic force

“…operation and low environmental requirement [25,26]. With these prominent advantages, MFM has become one of the most widespread and important methods for the analysis of individual MNPs.…”