“…The phase transition of CdTiO 3 has not been examined thoroughly enough, and the questions, about the crystal structure CdTiO 3 in the ferroelectric state, how the structure changes of the phase transition, and why the ferroelectricity occurs, have not been solved yet. In order to clarify the nature of the ferroelectric phase transition in CdTiO 3 , we carried out various studies such as measurements of the dielectric constant, specific heat, pyroelectricity, and the low-temperature powder X-ray diffraction on polycrystalline CdTiO 3 [4][5][6]. These studies have shown that the ferroelectric phase transition in CdTiO 3 is of the displascive type and of the second-order and the ferroelectric Curie temperature is of about 80 K. However, we could not determine the space group of the ferroelectric phase by the Rietveld method, since the variations of the structure between the low-and high-temperature phases were too small [5].…”