Material softening by cation off-centering in Bi-based lead-free piezoelectric ceramics. (15th July 2021)

• Record Type: Journal Article
• Authors: Kim, Sangwook; Nam, Hyunwook; Fujii, Ichiro; Ueno, Shintaro; Moriyoshi, Chikako; Kuroiwa, Yoshihiro; Wada, Satoshi
• Is Part Of: Japanese journal of applied physics. Volume 60:Number SF(2021)
• Publication Date: 2021-07-15
• Subjects: Material softening -- Bi ion off-centering -- BiFeOamp;amp;lt;subamp;amp;gt;3amp;amp;lt;/subamp;amp;gt;-BaTiOamp;amp;lt;subamp;amp;gt;3amp;amp;lt;/subamp;amp;gt;; Physics -- Periodicals; 621.05
• DOI: 10.35848/1347-4065/ac0fb5
• Languages: English
• ISSNs: 0021-4922

Abstract

Abstract: The origin of material softening in BiFeO3 –BaTiO3 ceramics was assessed by studying the crystal structure and structural parameters. The crystal structure was investigated at 950 K by synchrotron radiation X-ray diffraction using structure refinement; structural parameters were calculated from the final structure refinement results. The crystal structure was cubic, with Bi 3+ ions off-centering into six equivalent neighboring sites along the ⟨100⟩ direction. We suggested that the stability of the Bi off-centering position and Bi off-centering displacement affects the material softening. The maximum material softening occurred in 0.70BiFeO3 –0.30BaTiO3 ceramics with the largest Bi ion off-centering displacement and smallest Bi–O bond length, which provided the stable Bi ion off-centering position. Therefore, the material softening is attributed to the stability of the Bi ion off-centering position and the Bi ion off-centering displacement. The suggested model of material softening can provide essential information for the design and development of next-generation lead-free piezoelectric materials.