X-Ray Topography of Magnetic Domains in Iron Whisker Crystals

Abstract

Magnetic domains in well annealed [001] whisker crystals have been studied by X-ray topography. The three-dimensional shape of the rectangular domain observed by the powder pattern technique was found to be a cuboid. Qualitative explanation is given to the image contrast of 90° domain walls by the dynamical theory of X-ray diffraction in distorted crystals. The lattice distortion around the line of intersection of 90° and 180° domain walls was determined by the analysis of butterfly images. It was also found that the 180° domain wall is made visible by the application of magnetic field.
Fringe patterns appeared when the whiskers took the closure domain structure across the axis and also were elastically bent to produce the serrated domain wall. Dynamical calculation proves that they are the moiré fringes produced by the double diffraction in the adjacent domains.
Some observations about whisker tips and kinked whiskers are also described.