Novel Raman spectroscopy of a strong high-k diffuse phase transition (Ba_{1∿span style='font-style: italic'>x}Sm_x)(Ti_{0.95∿span style='font-style: italic'>x/4}Ce_0.05)O₃ ceramics

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• 作者：Dan-Dan Han ; Qiao-li Liu ; Yan-Dong Wang ; Chang-Hao Wang ; Da-Yong Lu ; ^{cninjp11232000@yahoo.com" class="auth_mail" title="E-mail the corresponding author} ; ^{dylu@jlict.edu.cn" class="auth_mail" title="E-mail the corresponding author}
• 关键词：B. Defects ; C. Dielectric properties ; D. BaTiO3 and titanates ; Powders ; solid state reaction and sintering
• 刊名：Ceramics International
• 出版年：2016
• 出版时间：15 May 2016
• 年：2016
• 卷：42
• 期：7
• 页码：8815-8821
• 全文大小：3631 K

文摘

Novel Raman spectra were discovered in (Ba_1−xSm_x)(Ti_0.95−x/4Ce_0.05)O₃ (0.03≤x≤0.10) ceramics and investigated in relation to the fluorescent effect of Sm³⁺ ions. Special interest was paid to analyze the dielectric response and defect chemistry associated with the structural evolution by X-ray diffraction (XRD), scanning electron microscopy (SEM), electron paramagnetic resonance (EPR), Raman spectroscopy (RS), and dielectric measurements. Complete solid solutions, known as BS5TC5 and BS6TC5 for (Ba_1−xSm_x)(Ti_0.95−x/4Ce_0.05)O₃ ceramics were found to form at x=0.05 and 0.06 (approximately) and exhibit a cubic structure and a non-uniform microstructure. BS6TC5 exhibited a strong high-k   diffuse phase transition (DPT) behavior (${ϵ}_{\mathrm{m}}^{\prime }$=9300, T_C=78 °C), a lower dielectric loss (tan δ<0.05), and a feature of mixed valence at Ba sites (Sm³⁺, Ce³⁺) and Ti sites (Sm³⁺, Ce⁴⁺). The BSTC ceramics with x=0.09 met the Y5V specification. A weak g=2.004 EPR signal associated with ionized Ti-vacancy defects appeared in single-phase ceramics.