Dielectric loss behaviour of cadmium iodide polytypic crystals

The loss spectra of several ordered/disordered parent and polytypic crystals of CdI₂ have been studied. The region of interest is seen to lie in the frequency range 0.1–3 kHz where several peaks are found to occur. While, in general, three prominent peaks occur in the region ～ 1 to ～ 3 kHz, disordered structures exhibit additional larger peaks below 1 kHz. The peaks occuring in the 1–3 kHz region arise due to inherent point defects present in the crystals and those occuring below 1 kHz and singular to the disordered structures are attributed to a resonance absorption effect embodying interfacial polarization which arises due to the occurence of dislocation dipoles which are responsible for the creation of the disorder.