Lorentz Microscopy Determination of Domain-Wall Width in Thick Ferromagnetic Films

Width of the 180° domain wall in Ni–Fe alloy films as a function of film thickness up to 1800 Å was measured using the defocused mode of Lorentz microscopy. For the thinner films, the measured wall widths are in good agreement with earlier data obtained by Fuchs. For films thicker than 800 Å, the wall width increases with film thickness to about 9000 Å at 1800 Å film thickness. The validity of the classical determination of wall width is discussed.