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 / Lo Presti L.; Parravicini J.; Soave R.; Parravicini G.; Mauri M.; Loconte L.; Di Mei F.; Falsi L.; Tartara L.; Binetti S.; Agranat A.J.; Delre E.. - In: PHYSICAL REVIEW. B. - ISSN 2469-9950. - ELETTRONICO. - 102:(2020), pp. 214110-214110. [10.1103/PhysRevB.102.214110]

Observation of an exotic lattice structure in the transparent KTa1-xNbx O3 perovskite supercrystal

Parravicini J.
;
2020

Abstract

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.
2020
102
214110
214110
Lo Presti L.; Parravicini J.; Soave R.; Parravicini G.; Mauri M.; Loconte L.; Di Mei F.; Falsi L.; Tartara L.; Binetti S.; Agranat A.J.; Delre E....espandi
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Utilizza questo identificatore per citare o creare un link a questa risorsa: https://hdl.handle.net/2158/1230042
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