Interference Fringes in Electron Micrographs of Magnesium Oxide

抄録

The striations, or so called equal thickness fringes, appearing in electron micrographs of magnesium oxide, have been studied in detail. It was found that the spacing of the striations ranges from 50 to several hundred Ångstroms, depending on the index of reflexion, azimuth, and glancing angle. The explanation of the striations is given by the dynamical theory applied to a wedge-shaped crystal. Calculated spacings of the striations as a function of azimuth and glancing angle are compared with observed values, giving fairly good agreement. Some newly found crystal shapes other than cubic and the effect of simultaneous reflexions on the striations are also described.