Phase transitions in lead-free piezoelectric ceramics: Study of local atomic structure Journal Article


Author(s): Lemeshko, Mikhail P; Nazarenko, Elena S; Gonchar, Anastasia A; Reznichenko, Larisa A; Mathon, Olivier; Joly, Yves; Vedrinskiǐ, Rostislav V
Article Title: Phase transitions in lead-free piezoelectric ceramics: Study of local atomic structure
Affiliation
Abstract: Local atomic structure of the piezoelectric ceramics KxNa 1-xNbO3 (x≤0.00, 0.05, 0.30, 0.40, 0.50 and 0.65) is studied in all phase regions (10 K-1023 K) using Nb K-edge extended X-ray absorption fine-structure (EXAFS) spectroscopy. We have shown the validity of a new spherical model for phase transitions on the basis of both fitting of EXAFS signal in the R-space and differential EXAFS analysis. Within this model the Nb atoms are located on the surfaces of small spheres of constant radii surrounding centers of NbO6 octahedrons in all phases. The distribution of the Nb atom on this surface changes during phase transitions. Besides, the analysis of local structure reveals that the geometry of NbO6 octahedra does not depend on the x value at each temperature, whereas the octahedra rotation angles do.
Journal Title: EPL
Volume: 77
Issue 2
ISSN: 02955075
Publisher: IOP Publishing Ltd.  
Date Published: 2007-01-11
Start Page: Article number: 26003
DOI: 10.1209/0295-5075/77/26003
Open access: no