Related Experiment Video
Updated: Feb 5, 2026

Measuring the Complete-arch Distortion of an Optical Dental Impression
Published on: May 30, 2019
Multistep coupling of preexisting local ferroic distortions in PbTiO3 above the Curie temperature
I Margaritescu1, K Datta1, B Mihailova1
1Department of Earth Sciences, University of Hamburg, Grindelallee 48, 20146 Hamburg, Germany.
Abstract:
Temperature-dependent Raman spectroscopic analyses were performed for the prominent ferroelectric PbTiO3 in the temperature range 130-1040 K, focusing particularly on its paraelectric state above the Curie temperature [Formula: see text] K. The temperature evolution of the anomalous Raman scattering reveals that not only local ferroic distortions persist at temperatures well above [Formula: see text], but also there is a sequence of different coupling processes preceding the appearance of long-range ferroelectric order at [Formula: see text]. Our results indicate that, similar to relaxor ferroelectrics, the paraelectric phase of PbTiO3 can be considered as an ergodic system of local ferroic distortions, which only on average appears to have cubic symmetry.
Related Concept Videos
¹H NMR: Interpreting Distorted and Overlapping Signals
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...
Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
Spin–Spin Coupling: Three-Bond Coupling (Vicinal Coupling)
The extent of coupling depends on the C‑C bond length, the two H‑C‑C angles, any electron-withdrawing substituents, and the dihedral angle between the involved orbitals. The...
G-protein Coupled Receptors
Spin–Spin Coupling: One-Bond Coupling
Couple
A typical example to understand this concept is tightening a bolt with a lug wrench. A...

