A spin-related contrast effect Visibility of 180° ferromagnetic domain walls in unpolarized neutron diffraction topography

Abstract
180° ferromagnetic domain walls have been observed in unpolarized neutron diffraction topographs of good Fe-3% Si single crystals, although they are not visible on X-ray topographs. The contrast is interpreted in terms of the dynamical theory of neutron diffraction in almost perfect magnetic crystals, by invoking the reflection of wave fields at the boundary.