Barkhausen noise visualized in real space (Invited Paper)

During magnetization reversal of ferromagnets random flux changes occur, which are responsible for the Bark-hausen noise. Using magnetic force microscopy, this noise can be visualized in real space so that individual Barkhausen events can be distinguished and analyzed with respect to size and location. Reducing the external field from saturation to zero in a granular ferromagnetic La0.7Sr0.3MnO3 thin film, the observed power law size distribution of growth events is discussed with respect to self-organized criticality and domain wall motion through a disordered medium.