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The NbO 6 octahedral distortion and phase structural transition of Eu 3+ ‐doped K 0.5 Na 0.5 NbO 3 – x LiNbO 3 ferroelectric ceramics
Author(s) -
Wang Jia,
Luo Laihui
Publication year - 2018
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.15180
Subject(s) - photoluminescence , natural bond orbital , ferroelectricity , materials science , tetragonal crystal system , raman spectroscopy , orthorhombic crystal system , analytical chemistry (journal) , phase transition , ferroelectric ceramics , octahedron , crystallography , mineralogy , dielectric , crystal structure , chemistry , condensed matter physics , density functional theory , optics , physics , optoelectronics , computational chemistry , chromatography
A small quantity of Eu 3+ ions were doped in the lead‐free ferroelectric K 0.5 Na 0.5 NbO 3 – x LiNbO 3 ( KNN – x LN , 0 ≤ x ≤ 0.08) ceramics to investigate the NbO 6 octahedral distortion induced by the increasing LN content. In addition, the phase structure, ferroelectric, and photoluminescence properties of K 0.5 Na 0.5 NbO 3 – x LiNbO 3 :0.006Eu 3+ ( KNN – x LN :0.006Eu 3+ ) lead‐free piezoelectric ceramics were characterized. All the X‐ray diffraction, Raman spectra, dielectric constant vs temperature measurements and the photoluminescence of Eu 3+ ions demonstrated that the prepared ceramics undergo a polymorphic phase transition ( PPT , from orthorhombic to tetragonal phase transformation) with the rising LN content, and the PPT region locates at 0.05 ≤ x ≤ 0.06. The ferroelectric properties, Raman intensity ratios and photoluminescence intensity ratios show similar variations with the increasing LN content, all with a maximum value achieved at the PPT region. We believe that the close relationship among the ferroelectric properties, Raman intensity ratios, and photoluminescence intensity ratios is caused by the NbO 6 octahedral distortion. The photoluminescence of Eu 3+ ion was discussed basing on the crystal‐symmetry principle and Judd‐Ofelt theory.