Advances in high resolution magnetic force microscopy

This paper reports the advancements in high resolution magnetic force microscopy (MFM). The MFM image formation results from the interaction of the magnetization distribution of the MFM tip with the stray magnetic field emanating from the sample. The force on the tip can easily be calculated from the gradient of the magnetostatic energy of the tip in the field of the sample. Lateral resolution can be enhanced by optimizing the minimal measurable frequency shift and the instrument transfer function. The demonstration of the power of quantitative and high lateral resolution MFM is shown by determining the local distribution of the uncompensated spin density at the interface of a thin ferromagnetic (FM) Co/Pt multilayer and a thin antiferromagnetic (AF) CoO film. Quantitative analysis of the MFM data reveals that the contrast at zero-field is due to the magnetic domains of the FM layer and the much weaker contrast observed in high fields is due to a small fraction of uncompensated spins at the AF/FM interface.