Domain-wall imaging by magnetic force microscopy

The near-surface microfield emanating from 90° and 180° Bloch walls in perfect iron single crystals was imaged by magnetic force microscopy. Characteristic differences in field magnitude and symmetry were obtained for the two types of walls. Along subdivided 180° walls, the polarization reversal, associated with the presence of a Bloch line, was clearly detected. Small variations of the microfield along individual walls are attributed to near-surface crystalline defects of the samples. It is concluded that magnetic force microscopy is particularly suitable for imaging domain-wall microfields closely above the sample surface in a nondestructive way. Typical lateral resolutions are somewhere between 10 and 100 nm depending on the probe dimensions actually employed