--- res: bibo_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. @eng bibo_authorlist: - foaf_Person: foaf_givenName: Mikhail foaf_name: Mikhail Lemeshko foaf_surname: Lemeshko foaf_workInfoHomepage: http://www.librecat.org/personId=37CB05FA-F248-11E8-B48F-1D18A9856A87 orcid: 0000-0002-6990-7802 - foaf_Person: foaf_givenName: Elena foaf_name: Nazarenko, Elena S foaf_surname: Nazarenko - foaf_Person: foaf_givenName: Anastasia foaf_name: Gonchar, Anastasia A foaf_surname: Gonchar - foaf_Person: foaf_givenName: Larisa foaf_name: Reznichenko, Larisa A foaf_surname: Reznichenko - foaf_Person: foaf_givenName: Olivier foaf_name: Mathon, Olivier foaf_surname: Mathon - foaf_Person: foaf_givenName: Yves foaf_name: Joly, Yves foaf_surname: Joly - foaf_Person: foaf_givenName: Rostislav foaf_name: Vedrinskiǐ, Rostislav V foaf_surname: Vedrinskiǐ bibo_doi: '10.1209/0295-5075/77/26003 ' bibo_issue: '2' bibo_volume: 77 dct_date: 2007^xs_gYear dct_publisher: IOP Publishing Ltd.@ dct_title: 'Phase transitions in lead-free piezoelectric ceramics: Study of local atomic structure@' ...