کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1331791 | 979015 | 2006 | 9 صفحه PDF | دانلود رایگان |
The perovskite-type oxides Ba1−xLax(1−y)/2Euxy/2Nax/2TiO3 (0⩽x ⩽0.5 and xy=0.04xy=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 Pm3¯m 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.
Temperature dependence of dielectric permittivity of Ba1−xLax(1−y)/2Euxy/2Nax/2TiO3 (0⩽x ⩽0.45 and xy=0.04xy=0.04) ceramics at 1 kHz.Figure optionsDownload as PowerPoint slide
Journal: Journal of Solid State Chemistry - Volume 179, Issue 12, December 2006, Pages 4011–4019