Phase transition sequence in ferroelectric Aurivillius compounds investigated by single crystal X-ray diffraction

摘要

The investigation of the phase transition sequence in SrBi_2Ta_2O_9 (SBT) and SrBi_2Nb_2O_9 (SBN) is reported using single-crystal X-ray diffraction. By monitoring specific reflections as a function of temperature, sensitive either to the superstructure formation or to polar displacements, it was possible to check the existence or not of an intermediate phase. This latter was confirmed in SBT, but within experimental accuracy could not be detected in SBN.