In Situ control and modification of the probe magnetization state for accurate magnetic force microscopy

Electrostatic tip-sample interactions currently represent the main limitation to accurate quantitative analysis of magnetic\udforce microscopy (MFM) data. Controlled magnetization MFM (CM-MFM) represents a smart solution to overcome this limitation\udas it allows one to identify electrostatic artifacts and to subtract them from standard MFM images, thus enabling the quantitative\udinvestigation of magnetic properties of materials at the nanometer scale. CM-MFM, however, requires not only the magnetization,\udbut also the in situ accurate demagnetization of the MFM probe. In particular, the latter represents a crucial step for the complete\udremoval of electrostatic artifacts. In this work, we describe two different methods to depolarize the MFM tip, based on the application\udof the coercive remanent magnetic field of the tip and on a damped alternating magnetic field, respectively. The two techniques\udare escribed and compared to emphasize their specific advantages and limitations