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Distinct temperature behavior of the local structure of (1‐x)PbTiO 3 ‐xBiNi 0.5 Ti 0.5 O 3 at the morphotropic phase boundary
Author(s) -
Margaritescu Irina,
Datta Kaustuv,
Chen Jun,
Mihailova Boriana
Publication year - 2020
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.5885
Subject(s) - phase boundary , raman spectroscopy , ferroelectricity , curie temperature , phase transition , atmospheric temperature range , phase (matter) , dielectric , materials science , polar , crystallography , chemistry , analytical chemistry (journal) , condensed matter physics , thermodynamics , physics , ferromagnetism , optoelectronics , organic chemistry , chromatography , optics , astronomy
Temperature‐dependent Raman spectroscopy was used to study the composition‐ and temperature‐driven structural transformations in the (1‐ x )PbTiO 3 ‐ x BiNi 0.5 Ti 0.5 O 3 solid solution, exhibiting a morphotropic phase boundary (MPB) at x MPB ∼0.55 and a relatively high Curie temperature ( T C ∼680 K at x MPB ). The analyses were carried out on ceramic samples, covering a wide temperature range across T C (100–1100 K) and several compositions across x MPB (0–0.70). The results reveal the presence of local ferroic distortions in the paraelectric phase of all compounds and strong composition‐induced enhancement of the order‐disorder phenomena across the para‐to‐ferroelelctric phase transition. The MPB compound is distinct by the absence of any temperature dependence of the wavenumber of the lowest‐energy A‐cation vibrational mode as well as by an equal dynamical weight of BO 6 octahedral distortions and tilts below T C . The former indicates that at the MPB, the local‐scale structural polarity associated with the A site is purely composition‐driven, while the latter reveals competing local‐scale polar and antiferodistortive orders related to the B‐site sublattice in the ferroelectric state, which do not vanish but become energetically indistinguishable in the paraelectric state.