Dielectric tunability of barium strontium titanate/silicone-rubber composite

被引:53
作者
Liou, JW [1 ]
Chiou, BS
机构
[1] Natl Chiao Tung Univ, Dept Elect Engn, Hsinchu 300, Taiwan
[2] Natl Chiao Tung Univ, Inst Elect, Hsinchu 300, Taiwan
关键词
D O I
10.1088/0953-8984/10/12/015
中图分类号
O469 [凝聚态物理学];
学科分类号
070205 ;
摘要
The dielectric tunability, which is defined as the percentage change of the permittivity under DC biasing, is over 30% for polycrystalline barium strontium titanate (BST) under a field of 5000 V cm(-1) at around the Curie peak. Various volume fractions (18%, 40%, 52%, and 64%) of BST powder are mixed with silicons rubber to obtain a multi-phase dielectric composite. The effective permittivity of the composite follows the Maxwell-Garnett relation with a shape parameter of about 14 for volume fractions below 52%. The dielectric tunabilities at 5000 V cm(-1) for the samples made with 52% and 64% powder are about 0.7% and 7.4%, respectively. The results are compared to the dielectric tunabilities obtained on the basis of series, parallel, and logarithmic models. It is suggested that the dielectric tunability is enhanced when a sample with a more continuous BST powder phase is obtained. An increase of the permittivity with a small DC field applied to the composite is attributed to the effect of polarization of the interface between the BST and silicone-rubber phases.
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页码:2773 / 2786
页数:14
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