Curious phase transformations in polytypic crystals of cadmium iodide

Abstract

Abstract Cadmium iodide polytypes undergo phase transformation when annealed under vacuum (10−4 Torr) at temperatures ranging between 250 and 280°C. A curious type of transformation in which identity period of the polytypes remains the same but stacking sequence of atomic layers changes, was found when the crystals were annealed at relatively lower temperatures (≈240°C). Such transformations have been discussed in detail and analysed in the light of the experimental evidences obtained. A possible mechanism for this type of transformation has been suggested in terms of stacking faults.