Decomposition of calcium fluoride and strontium fluoride in the electron microscope

Abstract

Thin fragments of calcium fluoride and strontium fluoride crystals have been prepared which are suitable for examination by transmission electron microscopy. After a short irradiation by the electron beam, Moiré patterns appear and these have been attributed to the partial decomposition of the fluorides, resulting in the formation of metallic calcium or strontium in a parallel orientation to the undecomposed fluorides. After further irradiation the patterns become diffuse and eventually disappear.