MENG Ling1, YAO Guo-guang2, ZHANG Dan1, DING Lan-fang1, MA Jian-li1, LIU Peng1*, CHEN Yi-wei3
(1 College of Physics and Information Technology, Shaanxi Normal University, Xi′an 710062, Shaanxi, China; 2 Department of Applied Mathematics and Applied Physics, Xi′an Institute of Posts and Telecommunications, Xi′an 710121, Shaanxi, China; 3 College of Telecommunications Engineering, Jilin University, Changchun 130012, Jilin, China)
Abstract:
Ba(ZrxTi1-x)O3（BZT，x=0.2，0.25，0.3）ceramics are prepared by using a traditional ceramic processing. The effects of the concentration of Zr on the microstructures, dielectric properties and tunability of BZT ceramics are investigated. The dielectric constants as a function of temperature at different frequencies show that the ceramics have characteristics of ferroelectrics with diffused phase transition, and the ceramic sample of x=0.3 exhibites a typical relaxor ferroelectric behavior. In the range of temperature from 193 to 323 K, the dielectric tunabilities of all the samples can reach above 10% and is a little stronger in ferroelectric state than that of paraelectric state. The experimental results is explained with the points of ferroelectric domains and Nano-micro-polarity. The tunabilities and the figure of merit measured at 300 K under the biasing field of E=1.5 kV/mm for x=0.25 are 49.5% and 49.11.
KeyWords:
Ba(ZrxTi1-x)O3; diffuse phase transition; dielectric tunability; figure of meritBaTiO3基陶瓷因为具有高的介电常数、电场可调性和居里温度可调特征被广泛应用在微波介质可调领域，包括可调电容器［1］、移相器［2,3］、随机动态存储器［4］ (DRAM)等．高的介电常数和低的介质损耗使得（Ba1－xSrx）TiO3［5］（BST）成为较理想的材料之一，但这类材料的温度稳定性和高场下的漏导电流还需要进一步改善．由于Zr4+比Ti4+稳定［6,7］，与BST相比， Ba(ZrxTi1-x)O3（BZT）中Ti4+与Ti3+之间的电子跳跃引起的电导较小，这使得BZT有希望成为取代BST的材料．作者利用X射线衍射、低温介电温谱以及偏压下介电响应，研究不同Zr含量对陶瓷的微观结构、介电弛豫和介电可调度的影响，得到了较宽温度范围（193～363 K）的介电可调度，为其在微波可调器件中的应用提供实验依据．
