Quantification of magnetic force microscopy images using combined electrostatic and magnetostatic imaging

A method for calibrating the force gradients and probe magnetic moment in p hase-contrast magnetic force microscopy (MFM) is introduced. It is based up on the combined electrostatic force microscopy EFM and MFM images of a cond ucting non magnetic metal strip. The behavior of the phase contrast in EFM is analyzed and modeled as a finite area capacitor. This model is used in c onjunction with the imaging data to derive the proportionality constant bet ween the phase and the force gradient. This calibration is further used to relate the measured MFM images with the field gradient from the same conduc ting strip to derive the effective magnetic moment of the probe. The knowle dge of the phase-force gradient proportionality constant and the probe's ef fective moment is essential to directly quantify field derivatives in MFM i mages. (C) 1998 American Institute of Physics. [S0021-8979(98)27711-5].