STUDY OF THE LEAKAGE FIELD OF MAGNETIC FORCE MICROSCOPY THIN-FILM TIPS USING ELECTRON HOLOGRAPHY

Electron holography is applied for the study of the leakage field of t hin-film ferromagnetic tips used as probes in magnetic force microscop y. We used commercially available pyramidal tips covered on one face w ith a thin NiCo film, which were then placed in a high external magnet ic field directed along the pyramid axis. Good agreement between simul ated and experimental electron phase difference maps allows to measure the local flux from the ferromagnetic tips and therefore to evaluate the perturbation induced by the microprobe stray field on the sample a rea. (C) 1996 American Institute of Physics.