Asymmetric 180° Domain Walls in Single Crystal Iron Films

Abstract

New kinds of contrasts of domain wall images have been observed by 1000 kV Lorentz microscopy for single crystal iron films with the thickness ranging 1000–2600 Å. The observed asymmetric contrast agrees with a numerically calculated contrast for the two-dimensional 180° wall with a magnetostatic energy free structure. The wall width of the asymmetric wall is much broader than that of the Bloch wall. The experimentally observed widths of 1500 Å to 3000 Å are comparable with the calculated value of 2200 Å for the 2000 Å thick iron film.
The wall energy of the asymmetric 180° wall for a thickness range 400–3500 Å is always much lower than that of the 180° Bloch wall.