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Structural Instability during Cubic‐Tetragonal Transformation in Lead Titanate Single Crystals
Author(s) -
Chou ChenChia,
Hou ChunShou
Publication year - 1999
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1999.tb01910.x
Subject(s) - tetragonal crystal system , instability , materials science , diffraction , condensed matter physics , phase (matter) , crystallography , lattice (music) , optics , crystal structure , chemistry , physics , organic chemistry , mechanics , acoustics
In this paper, we report the structural instability and premartensitic transformation phenomena in PbTiO 3 single crystals during tetragonal‐to‐cubic phase transformation and vice versa, studied using hot‐stage X‐ray diffraction and polarized optical microscopy. The present results suggest that theoretical predictions of a habit plane based upon phenomenological crystallographic theory and experimental values may vary over a certain range if the lattice perturbation due to crystal defects and structural instability during transformation are taken into consideration. In the course of the tetragonal‐to‐cubic phase transformation, X‐ray diffraction shows a broad peak, associated with an intermediate phase, up to several tens of degrees above T c . Using heating‐stage optical microscopy, patches of bright bands and moiré fringes were often seen to form in advance prior to the arrival of a phase front during cubic‐to‐tetragonal transformation, especially when the specimens exhibited severe internal stress, indicating a generalized lattice perturbation during phase transformation.