We perform redundant x-ray diffraction versus temperature experiments in bulk transparent KTN. We find a violation of the standard perovskite cubic-to-tetragonal symmetry breaking at the Curie point in the form of an orthorhombic cell distortion. The lattice distortion spans coherently macroscopic volumes of the sample and is characterized by a negative-to-zero thermal volume expansion. Dielectric measurements and calorimetry indicate that the anomalous behavior is not associated to a distinct thermodynamic phase. The comparison of linear and nonlinear optical scattering experiments with structural data suggests that the lattice distortion is a consequence of strain relaxation to a 3D superlattice of polarization vortices.
Observation of an exotic lattice structure in the transparent KTa1-xNbx O3 perovskite supercrystal / L. Lo Presti, J. Parravicini, R. Soave, G. Parravicini, M. Mauri, L. Loconte, F. Di Mei, L. Falsi, L. Tartara, S. Binetti, A.J. Agranat, E. Delre. - In: PHYSICAL REVIEW. B. - ISSN 2469-9950. - 102:21(2020 Dec 17).
Titolo: | Observation of an exotic lattice structure in the transparent KTa1-xNbx O3 perovskite supercrystal | |
Autori: | ||
Parole Chiave: | perovskite; X-ray diffraction; nonlinear response; dielectric spectroscopy; hypervortex; supercrystal | |
Settore Scientifico Disciplinare: | Settore CHIM/02 - Chimica Fisica Settore CHIM/03 - Chimica Generale e Inorganica | |
Data di pubblicazione: | 17-dic-2020 | |
Rivista: | ||
Tipologia: | Article (author) | |
Digital Object Identifier (DOI): | http://dx.doi.org/10.1103/PhysRevB.102.214110 | |
Appare nelle tipologie: | 01 - Articolo su periodico |
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