Structural phase transition due to La substitution in Bi4Ti3O12 |
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| Authors: | Di Wu Bin Yang Aidong Li |
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| Affiliation: | 1. National Laboratory of Solid State Microstructures and Department of Materials Science and Engineering , Nanjing University , Nanjing, China diwu@nju.edu.cn;3. Center for Condensed Matter Science and Technology , Harbin Institute of Technology , Harbin, China;4. National Laboratory of Solid State Microstructures and Department of Materials Science and Engineering , Nanjing University , Nanjing, China |
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| Abstract: | The structure of Bi4?x La x Ti3O12 (BLaTx) as a function of La content from x = 0.00 to 1.25 was studied by Raman spectroscopy and X-ray diffraction (XRD). It was observed that the Raman modes evolve discontinuously at about x = 1.00, which indicates a structural phase transition. Specifically, the B 2g and B 3g Raman modes shown evidences to coalesce into E g modes with increasing La content. The evolution of Raman modes corresponds to the weakening of ferroelectric orthorhombic lattice distortion with increasing La substitution when x ≤ 1.00 and the final transition into the paraelectric tetragonal structure at higher La content. XRD and electrical measurement results confirm this phase transition by the observation that diffraction peaks from (200) and (020) planes of BLaT0.75 coalesce into one peak in BLaT1.25 and by the corresponding disappearance of remanent polarisation. The impact of La substitution on electrical properties of BLaTx is discussed briefly. |
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| Keywords: | ferroelectrics layered perovskites bismuth titanate crystal structure Raman spectroscopy |
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