Changing the polar order using different sintering methods. Issue 13 (1st July 2021)

• Record Type: Journal Article
• Authors: Bai, Chenxing; Wei, Yongxing; Jin, Changqing; Zhu, Weitong; Jian, Zengyun
• Is Part Of: Ceramics international. Volume 47:Issue 13(2021)
• Page Start: 19191
• Page End: 19197
• Publication Date: 2021-07-01
• Subjects: BKT -- Two-step sintering method -- Spontaneous transition -- Relaxor-ferroelectric; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2021.03.266
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: In this study, solid solution ceramics (1–x)Bi0.5 K0.5 TiO3 –xBi0.2 Sr0.7 TiO3 (x = 0.1, 0.15 and 0.2, abbreviated as BKST1 for a one-step sintering method and as BKST2 for a two-step sintering method) were prepared using two different sintering methods. The BKST1 ceramics exhibited an average cubic structure, while the BKST2 ceramics had tetragonal distortions. As the Bi0.2 Sr0.7 TiO3 content increased, spontaneous relaxor-ferroelectric transition disappeared in the BKST1 ceramics owing to the formation of the polar nanoregions (PNRs). The compositions developed using the two-step sintering method exhibited a noticeable dielectric anomaly with respect to spontaneous relaxor-ferroelectric transitions. Double ferroelectric hysteresis loops appeared near the ergodic relaxor-ferroelectric (or non-ergodic relaxor) transition points. The relationship between the piezoelectric coefficient ( d 33 ) and compositions suggested that 0.15BKST1 exhibited the optimum piezoelectric properties ( d 33, 128 pC/N). The 0.15BKST ceramic developed using the one-step sintering method had a low depolarisation temperature (~176 °C in 0.15BKST1 compared to ~227 °C in 0.15BKST2). The improved piezoelectric properties were attributed to the electrical field-induced transformation from PNRs to the long-range ferroelectric ordering as evidenced by the poling effects on the XRD patterns and dielectric behaviours.