Dielectric and piezoelectric properties of (1鈭?span style='font-style: italic'>x)Ba_0.7Sr_0.3TiO₃鈭?span style='font-style: italic'>xBa_0.7Ca_0.3TiO₃ perovskites

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• 作者：Jiangying Wang^a ; ^{wjyliu@163.com} ; Xiaoying Zhang^a ; Jingji Zhang^a ; Huiling Li^b ; Zhengfa Li^a
• 关键词：A. Ceramics ; D. Phase transitions ; D. Dielectric properties ; D. Piezoelectricity
• 刊名：Journal of Physics and Chemistry of Solids
• 出版年：2012
• 期刊代码：69_00223697
• 类别：ch
• 出版时间：July, 2012
• 卷：73
• 期：7
• 页码：957-960
• 文件大小：582 K

摘要

Dielectric and piezoelectric properties of (1鈭?em>x)Ba_0.7Sr_0.3TiO₃鈭?em>xBa_0.7Ca_0.3TiO₃ (BST鈭?em>xBCT) (x=0.2-0.9) perovskite ceramics have been investigated. BCT has fully incorporated into BST lattice, forming a complete perovskite solid solution, whose lattice constant 蠂 decreases almost linearly with increase in x from 0.2 to 0.4, while showing an anomalous expansion at 0.4<x鈮?.6. This, together with the deviation of tetragonal-orthorhombic phase transition temperature (T_O-T) from the linear relation T_O-T (K)=鈭?03.7x+239.3 at x=0.5, suggests that a small amount of Ca²⁺ has substituted for Ti⁴⁺. Curie temperature T_C increases linearly with increase in x from 0.2 to 0.9, which is mainly contributed to the increase of the Ba/Sr ratio. The calculated degree of relaxation (纬) is in the range of 1.41-1.53, indicating that the BST-xBCT ceramics are ferroelectric materials with diffuse phase transition. Strain and piezoelectric constant (d₃₃) decrease with increasing x, whereas planar electromechanical coefficient (k_p) reaches a maximum (17.0%) at x=0.6.