Growth and electrical properties of Na_0.5Bi_0.5TiO₃-K_0.5Bi_0.5TiO₃ lead-free single crystals by the TSSG method

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• 作者：Renbing Sun^a ; ^{renbingsun@hotmail.com" class="auth_mail" title="E-mail the corresponding author} ; Jinzhi Wang^a ; Fang Wang^a ; Tangfu Feng^a ; Fengyu Kong^a ; Xianglian Liu^a ; Yanlong Li^a ; Haosu Luo^b
• 关键词：Lead-free ; Crystal growth ; Dielectric property ; Piezoelectric property
• 刊名：Ceramics International
• 出版年：2016
• 出版时间：October 2016
• 年：2016
• 卷：42
• 期：13
• 页码：14557-14564
• 全文大小：2545 K

文摘

A series of NBT-KBT lead-free crystals with dimensions of Φ 35×10 mm were successfully grown by the TSSG method. The as-grown crystals possess rhombohedral perovskite structure at room temperature. The curves ε(T) for all crystals show two abnormal dielectric peaks. The depolarization temperatures T_d derived from the first peak of curves tan δ(T) vary with the KBT content, which are 130, 150, 140, and 115 °C respectively, for (100−x)NBT−xKBT (x=5, 8, 12, 15) crystals, being well consistent with the T_d obtained from the temperature dependence of k_t. A notable thermal hysteresis, ΔT≈35 °C, for ferroelectric-antiferroelectric phase transition was also disclosed for 92NBT-8KBT crystal. The investigation of orientation dependence for electrical properties disclosed the dielectric parameters show weak anisotropy. The piezoelectric constants (d₃₃) are 147, 175, 205, 238 pC/N and the values of k_t are 38%, 52%, 52%, 54%, respectively for (100−x)NBT−xKBT (x=5, 8, 12, 15) crystals.