Structure refinement, dielectric, pyroelectric and Raman characterizations of Ba1−xLax(1−y)/2Euxy/2Nax/2TiO3 solid solution |
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Authors: | Najmeddine Abdelmoula Hamadi Khemakhem Mario Maglione |
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Institution: | a Laboratoire des Matériaux Ferroélectriques, Faculté des Sciences de Sfax, BP 802, 3018 Sfax, Tunisia b Institut de Chimie de la Matière Condensée de Bordeaux, ICMCB-CNRS Université Bordeaux I, 87, Avenue du Dr. A. Schweitzer, 33608 Pessac, France |
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Abstract: | The perovskite-type oxides Ba1−xLax(1−y)/2Euxy/2Nax/2TiO3 (0?x?0.5 and xy=0.04) were synthesized and characterized by X-ray diffraction as well as dielectric measurements and Raman spectroscopy. The crystal structure of these ceramics has been determined by the Rietveld refinement powder X-ray diffraction data at room temperature. These compounds crystallize at room temperature in tetragonal space group P4mm for 0?x?0.1 and in the cubic group for 0.2?x?0.5. The phase transition temperature TC (or Tm) decreases as x content increases. The degree of diffuseness of the phase transition is more pronounced for higher x content, implying the existence of a composition-induced diffuse phase transition of the ceramics with x?0.1. The evolution of the Raman spectra was studied as a function of various compositions at room temperature. The polarization state was checked by pyroelectric measurements. |
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Keywords: | Ceramic Rietveld refinement Perovskite Relaxor Pyroelectric Raman spectroscopy |
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