Phase and Structure Transformations in Mixed CsICsBr Crystals

Abstract

X‐ray methods are used to study the peculiarities of solid solution decomposition in mixed CsI‐CsBr crystals. This process is started at the surface and results in the polycrystalline layer formation. The structure of this layer inherits the morphology of the initial surface and is completed by the turning of crystallites to the texture axis 〈110〉. The solutions with small impurity content (< 7 %) are stable. It is shown that a high content of moisture stimulates the decomposition process. At the same time the hydrolysis of the crystallite surface essentially restricts the possibility of secondary recrystallization. The mixed crystals under consideration turn out to be instable, despite the closeness of iodine and bromine ionic radii.