English: Animation of moving domain walls in a ferromagnetic material caused by an external magnetic field, observed with a Kerr-effect microscope. The sample of non-oriented electrical steel was magnetised. The animation starts from a demagnetised state and shows the effect of applying an increasing magnetic field in a downwards direction. The animation ends when sample saturates (slow magnetisation, below 0.1 Hz). Light areas have magnetization directed upwards, dark areas have magnetization directed downwards. Width of the image = 0.1 mm. See also Image:Magnetic domain by Zureks.png