DECONVOLUTION OF MAGNETIC FORCE IMAGES BY FOURIER-ANALYSIS

A novel technique is presented which allows the "true" magnetic charge distribution of a sample to be obtained from a raw MFM image by deconvolution. The formation of magnetic force microscopy (MFM) images can be considered as a convolution of the tip response function and the divergence of the sample magnetization. The key element in this method is the tip response function which contains the information about the magnetic and geometric properties of the tip. This tip response function is obtained by imaging the flux emanating from the end of an ultra narrow single domain nickel strip which approximates a "point" magnetic charge. An MFM image of recorded bits obtained with the same tip is deconvolved utilizing Fourier transformation methods. By this means, the deconvolved image becomes tip independent and it is possible to achieve spatial resolutions as small as the width of the Ni strip which can be 10 nm wide.