Magnetic force microscopy (MFM) is a variety of atomic force microscopy,
where a sharp magnetized tip scans a magnetic sample; the tip-sample
magnetic interactions are detected and used to reconstruct the magnetic
structure of the sample surface.
In this work, we have used Dynamic (AC) noncontact
AFM (NC-AFM) mode. A mode which provide micrographs for
topography, oscillation amplitude changes and phase shift. Using the
autocorrelation Operator, we studied the anisotropy and periodicity in
magnetization distributions in different generations of floppy disks.