处于顺电相的Ba_(0.6)Sr_(0.4)TiO_3-Li_2O陶瓷极化机理的研究  

Research on Polarization Mechanism of Ba_(0.6)Sr_(0.4)TiO_3-Li_2O Ceramics under Paraelectric State

作　　者：张校飞 牛永斌 

机构地区：[1]湖北理工学院数理学院,湖北黄石435003

出　　处：《湖北理工学院学报》2017年第6期37-40,共4页Journal of Hubei Polytechnic University

基　　金：湖北理工学院引进人才项目(项目编号:12xjz02R)

摘　　要：Ba_(1-x)Sr_xTiO_3系列的铁电材料在偏置电场作用下具有强的介电非线性,在可调微波器件方面有广阔的应用前景。材料中极化实体在偏置电场作用下的极化行为反映出介电非线性的物理本质。采用柠檬酸盐法制备名义组成为Ba0.6Sr0.4Ti O3+0.5 wt.%Li2O(简称BSTL)的陶瓷样品,研究了样品的晶体结构和非线性介电性能。XRD分析结果和介电温谱表明陶瓷样品在室温下处于顺电相。P-E曲线和偏置电场下的介电性能表明陶瓷样品中存在极性微区(PNRs),该极性微区对样品的介电非线性具有一定程度的贡献。通过多重极化机制模型拟合,计算出PNRs的极化强度和尺寸分别为0.214μC/cm^2和5.76 nm。Perovskite ferroelectrics of barium strontium titantate series have strong dielectric nonlinearity in bias electric field and they are promising candidate materials for electrically tunable microwave devices. Polarization behavior of polar species in dielectrics reflects the physics information of dielectric nonlinearity. A nominal composition Ba0.6Sr0.4TiO3＋ 0. 5 wt. % Li2O was prepared by the citrate method. The crystal structure and nonlinear dielectric properties were investigated. XRD analysis and temperature dependence of dielectric constant and dissipation implied a paraelectric state for the ceramic specimen at room temperature. P-E relation curve and the dielectric behavior in bias electric field suggested the existence of nano-polar regions（ PNRs）,which contributed to the dielectric nonlinearity for the specimen. Through fitting to the multi-polarization model,the polarization strength and size of PNRs were determined to be 0. 214 μC/cm^2,5. 76 nm,respectively.

关 键 词：电介质材料 柠檬酸盐法 低温烧结 极化机理 极性微区 

分 类 号：O48[理学—固体物理]