Ferroelectric Phase Transition in CdTiO 3 Single Crystal

Single-crystal X-ray diffraction measurements at low temperature were carried out using the image-plate technique in the vacuum chamber at BL02B1 of SPring-8. The intensity data were collected at 20 K, 70 K, and 150 K, 36 photographs being taken at each temperature. The systematic extinctions observed at 20 K could be summarized as h = 2 n + 1 for ( hk 0) reflections. This observation together with the observations of the ferroelectricity at this temperature uniquely determine the space group as P 2 1 ma though a previous report suggested the space group to be Pn 2 1 a . The structure could be refined with this space group yielding R = 0.056 for 4359 reflections. The structure of CdTiO 3 at 150 K was found to be almost identical to the previously reported one, belonging to the space group Pnma .

Keywords:

• Cdtio 3
• X-ray Diffraction
• Crystal Structure
• Space Groups