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Title of article :
Structure analysis of bismuth sodium titanate-based A-site relaxor ferroelectrics by electron diffraction
Author/Authors :
Cheng، نويسنده , , Shun-Yu and Shieh، نويسنده , , Jay and Lu، نويسنده , , Hong-Yang and Shen، نويسنده , , Chang-Yi and Tang، نويسنده , , Yao-Chieh and Ho، نويسنده , , New-Jin، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2013
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Abstract :
This study investigates the microstructure, elemental distribution, diffuse phase transition (DPT) and crystalline phases of BNBK 85.4/2.6/12 lead-free ferroelectric ceramics, a high-strain bismuth sodium titanate-based relaxor system with complex A-site compositions. TEM electron diffraction studies indicate that the ceramics are close to a compositionally driven morphotropic phase boundary between a conventional rhombohedral (R) structure and a nanoscale tetragonal (T) structure. The ceramics exhibit a core–shell grain microstructure – the shell region shows a cubic average symmetry with the presence of tetragonal distortions; while the core region is of a mixture of T and R phases. Analysis of the corresponding superlattice reflections and dark-field images reveals an R phase-dominant core with the presence of R-twin domains. The high resolution TEM image of the shell region reveals the existence of T-phase nano-domains. The DPT behavior is mainly attributed to the heterogeneous distribution of cations of high valences and concentrations across the core–shell grains.
Keywords :
microstructure , TEM , Crystal symmetry , Bismuth sodium titanate , Relaxor ferroelectrics
Journal title :
Journal of the European Ceramic Society
Journal title :
Journal of the European Ceramic Society
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