Magnetic force microscopy (MFM) has been demonstrated as valuable technique for the
characterization of magnetic nanomaterials. To be analyzed by MFM techniques, nanomaterials
are generally deposited on flat substrates, resulting in an additional contrast in MFM images due to
unavoidable heterogeneous electrostatic tip-sample interactions, which cannot be easily distinguished
from the magnetic one. In order to correctly interpret MFM data, a method to remove the electrostatic
contributions from MFM images is needed. In this work, we propose a new MFM technique, called
controlled magnetization MFM (CM-MFM), based on the in situ control of the probe magnetization
state, which allows the evaluation and the elimination of electrostatic contribution in MFM images. The
effectiveness of the technique is demonstrated through a challenging case study, i.e., the analysis of
superparamagnetic nanoparticles in absence of applied external magnetic field. Our CM-MFM technique
allowed us to acquire magnetic images depurated of the electrostatic contributions, which revealed
that the magnetic field generated by the tip is sufficient to completely orient the superparamagnetic
nanoparticles and that the magnetic tip-sample interaction is describable through simple models once
the electrostatic artifacts are removed