X-ray topography of single crystal NiO

Abstract

Abstract A reflection and transmission x-ray study of single crystal NiO was made below the Néel temperature. Anti-ferromagnetic domains separated by several types of twin boundaries were clearly observed. The indices of diffraction planes which must be used to show the presence of the twin boundaries in x-ray topographs were derived. Non-crystallographically oriented sub-grain boundaries were also observed in the topographs. These boundaries seem to have little effect on domain walls passing through them. The average sub-grain misorientation was measured to be about 10′ of are. Although the domain walls were moved by mechanical stress, the sub-grain boundaries were immobile, even upon heating the crystal to 300°c.