Changes in magnetic domain structure of maraging steel studied by magnetic force microscopy

The paper presents results on whether and how the magnetic domain structure in maraging steel undergoes any change due to the aging process. It continues the works on application of correlation methods and fractal analysis into studies of magnetic properties of various steel alloys using Scanning Probe Microscopy. It is aimed at verifying the usefulness of the structure function for description of spatial changes in shape and orientation of magnetic domains, and the magnitude of magnetic stray field affected by the heat treatment. Obtained results suggest that despite vanishing magnetic tip-surface interaction, and hence vanishing magnetic stray field, magnetic domains remain nearly perfectly isotropic although randomly oriented. Similar to isotropic real surfaces, the fractal dimension of the magnetic domains turns out to be independent of the structural changes induced by the aging process, whereas the topothesy is found to vary within order of magnitude along with changes in the magnetic stray field. After all, obtained results lead to conclusion that the aging process leaves its fingerprints in the structure of the steel alloys, which can be studied using numerical analysis of images of magnetic interactions between vibrating tip and the stray field.