Effects of Li Substitution on the Structure and Ferroelectricity of (Na,K)NbO3
The structures of (1−x)(K0.5Na0.5)NbO3–xLiNbO3 were investigated by the X-ray Rietveld method at room temperature. It is surprising to find that the spontaneous polarization of orthorhombic phase reaches at the lowest value and the spontaneous polarization of tetragonal phase reaches at highest value at x=0.06. The lattice parameter of (K0.47Na0.47)NbO3–0.06LiNbO3, which was refined by using two phase model, reasonably described the structure change of the (1x)(K0.5Na0.5)NbO3–xLiNbO3. The temperature dependence of Raman spectroscopy study of the phase transition of (K0.47Na0.47)NbO3–0.06LiNbO3 showed that the increasing of temperature introduced a local disorder even above Tc. The degree of cation ordering determines the electrical properties of the ceramics.
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Document Type: Research Article
Department of Physical Chemistry, University of Science and Technology Beijing, Beijing 100083, China
State Key Laboratory for Advanced Metals and Materials, Department of Physical Chemistry, University of Science and Technology Beijing, Beijing 100083, China
Publication date: 2009-12-01