Y3+掺杂对Ba0.99La0.01TiO3陶瓷介电性能的影响

Effects of Y3+ Doping on Dielectric Properties of Ba0.99La0.01TiO3 Ceramics

以Ba0.99La0.01TiO3陶瓷为基体,采用传统固相反应法制备Ba0.99La0.01Ti1-xYxO3(0≤x≤0.04)陶瓷样品。通过XRD、SEM、LCR分析仪对陶瓷样品的晶体结构、微观形貌、介电性能进行了分析。结果表明:随着掺杂量增加,晶胞体积逐渐增大,在x=0.04时由四方相转变为立方相,当x≥0.01时,陶瓷样品出现了第二相。结合GULP代码模拟计算和实验数据可知陶瓷中Y^3+取代Ti位,主要存在Y3+与La^3+相互补偿和氧空位补偿。在x=0.02时,陶瓷发生了半导化,介电常数较大。介电常数峰值温度随着掺杂量的增大向低温方向移动,介电峰被展宽并呈现弛豫铁电体特征。

The Ba0.99La0.01T1-xYxO3(0≤x≤0.04) ceramics were prepared by conventional solid state reaction processing using Ba0.99La0.01TiO3 ceramics as matrix. The crystal structure, micro-morphology and dielectric properties of ceramic samples were studied by XRD, SEM, LCR analyser respectively. The results show that with the increasing of doping amount, the cell volume increases gradually. At x=0.04, the tetragonal phase is transformed into cubic phase. When x≥0.01,the second phase appears in the ceramic sample. Combined with GULP code simulated calculation and experimental datas, Y3+ substitute at Ti site compensating with La3+ and oxygen vacancy. When x=0.02, the ceramics turn into semiconducting ceramics, exhibiting a large dielectric constant. The dielectric peak temperature shifts to low temperature with the increasing of doping content, and the dielectric peak is broadened. With the increasing of doping content, the ceramic samples show relaxor ferroelectric behavior.