Enhanced thermal stability of (NaCe)‐multidoped CaBi2Nb2O9 by A‐site vacancies‐induced pseudo‐tetragonal distortion. Issue 10 (30th April 2018)

• Record Type: Journal Article
• Authors: Liu, Gang; Ren, Shengqiang; Wu, Chao; Wang, Dan; Li, Fenglian; Wu, Jiagang; Chen, Qiang
• Is Part Of: Journal of the American Ceramic Society. Volume 101:Issue 10(2018)
• Page Start: 4615
• Page End: 4626
• Publication Date: 2018-04-30
• Subjects: aurivillius‐type materials -- In situ XRD -- thermal depoling -- XRD rietveld refinement; Ceramics -- Periodicals; 620.1405
• DOI: 10.1111/jace.15724
• Languages: English
• ISSNs: 0002-7820

Abstract

Abstract: Although A‐site codoping of alkali metal and rare‐earth elements are known to effectively promote the d 33 of CaBi2 Nb2 O9 (CBN), its thermal depoling behavior cannot be well promised. In this work, piezoelectricity of CBN was effectively promoted by (NaCe) modification, and its thermal instability was caused by the lattice evolution from orthorhombic structure to pseudo‐tetragonal structure during thermal depoling process. A‐site vacancies could induce pseudo‐tetragonal distortion in Ca0.92 (Na0.5 Ce0.5 )0.08 Bi2 Nb2 O9 ceramic, which obviously enhanced the thermal stability of lattice by reducing the rotation of the Nb–O octahedron during the thermal depoling process, as compared with orthorhombic structure, thereby weakening the swing of spontaneous polarization ( P s ) and promoting the thermal depoling performance. Consequently, good thermal stability was obtained (remained 92% of initial d 33 after depoling at 600°C). Moreover, dominant role of oxygen vacancies in the electrical conduction and relaxation process promised that the introduction of small amount of A‐site vacancies would not influence the electrical properties obviously.