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Lattice dynamics and phase transitions in KNbO.sub.3./sub. and K.sub.0.5./sub.Na.sub.0.5./sub.NbO.sub.3./sub. ceramics
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SYSNO ASEP 0331199 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Lattice dynamics and phase transitions in KNbO3 and K0.5Na0.5NbO3 ceramics Title Dynamika mřížky a fázové přechody v keramikách KNbO3 and K0.5Na0.5NbO3. Author(s) Buixaderas, Elena (FZU-D) RID, ORCID
Nuzhnyy, Dmitry (FZU-D) RID, ORCID
Gregora, Ivan (FZU-D) RID, ORCID
Kamba, Stanislav (FZU-D) RID, ORCID, SAI
Berta, Milan (FZU-D) ORCID
Malič, B. (SI)
Kosec, M. (SI)Source Title IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control. - : Institute of Electrical and Electronics Engineers - ISSN 0885-3010
Roč. 56, č. 9 (2009), s. 1843-1849Number of pages 7 s. Language eng - English Country US - United States Keywords ferroelectrics ; lattice dynamics ; phonons Ir and Raman spectroscopy ; piezoelectrics ; THz spectroscopy Subject RIV BM - Solid Matter Physics ; Magnetism R&D Projects IAA100100701 GA AV ČR - Academy of Sciences of the Czech Republic (AV ČR) KAN301370701 GA AV ČR - Academy of Sciences of the Czech Republic (AV ČR) GA202/06/0403 GA ČR - Czech Science Foundation (CSF) CEZ AV0Z10100520 - FZU-D (2005-2011) UT WOS 000269298300011 DOI 10.1109/TUFFC.2009.1259 Annotation Phonons in both ceramic samples KNbO3 (KN) and K0.5Na0.5NbO3 (KNN-50) were investigated from 10 to 900 K by means of Raman, infrared, and THz spectroscopy. First-order transitions from cubic to tetragonal phases were detected at about 755 K (in KN) and 710 K (in KNN-50), where the first component of the polarization appears. Transitions from the tetragonal to the orthorhombic phases take place around 510 and 475 K, respectively. The last transitions from orthorhombic to rhombohedral phases are strongly first-order type. TC is shifted from 200 K in KN to about 90 K in KNN-50. All Raman active modes below 200 cm-1 disappear in KN but not in KNN-50. The overdamped soft mode present at high temperatures in the THz range changes its dielectric strength at each phase transition. Workplace Institute of Physics Contact Kristina Potocká, potocka@fzu.cz, Tel.: 220 318 579 Year of Publishing 2010
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