Crystal structure refinement and investigation of electrically heterogeneous microstructure of single phased Sr substituted BaTiO₃ ceramics

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• 作者：Monica Sindhu ; Neetu Ahlawat ; Sujata Sanghi ; Rekha Kumari ; Ashish Agarwal
• 关键词：Barium strontium titanate ; Rietveld refinement ; Impedance spectroscopy
• 刊名：Journal of Alloys and Compounds
• 出版年：2013
• 出版时间：25 October, 2013
• 年：2013
• 卷：575
• 期：Complete
• 页码：109-114
• 全文大小：1172 K

文摘

Single phased Sr substituted BaTiO₃ ceramics were synthesized via solid state reaction technique and were found to crystallise in tetragonal symmetry with P4mm space group using Rietveld refinement. With increase in Sr content the tetragonality was reduced and the Curie temperature decreased at rate of 3 K/mol % . The contribution of grain interiors and grain boundaries to conduction and relaxation mechanisms was discerned on basis of ac conductivity, impedance and modulus formalisms. Three conduction mechanisms were observed in grain interiors; two via conducting electrons from and and third one via oxygen vacancies itself. The relaxation at grain boundaries was attributed to the defect associate (). Saturated hysteresis loops confirmed the ferroelectric nature of the ceramics. The remnant polarization P_r and the coercive fields E_c decrease with increase in Sr content.