Er^(3+)掺杂对立方焦绿石陶瓷结构与介电性能的影响

Influence of Er^(3+) Doping on Structure and Dielectric Properties of α-Bi_(1.5)ZnNb_(1.5)O_7 Ceramics

采用固相反应法制备(Bi1.5–x Erx Zn0.5)(Zn0.5Nb1.5)O7(BEZN,x=0、0.05、0.10、0.15、0.20、0.25、0.30)陶瓷,研究了Er3+替代Bi3+对(Bi1.5Zn0.5)(Zn0.5Nb1.5)O7(BZN)陶瓷结构与介电性能的影响。结果表明:当Er3+掺杂量x<0.15 mol时,样品为单一α-BZN相;当x≥0.15 mol时,出现第二相。用分子动力学计算Er3+分别进入A、B位的溶解能结果可知,此时Er3+可能已进入B位。随Er3+掺杂量增加,Er3+进入晶格,BEZN陶瓷密度从6.999 g/cm3减小到6.680 g/cm3,有明显细化晶粒作用。一定频率(1 MHz)条件下,峰值介电常数随Er3+掺杂量增加而减小,弛豫峰温度范围介电常数变化量Δε逐渐减小,即弛豫峰逐渐宽化和平坦。

（Bil.5_xErxZn0.5）（Zn0.5Nb1.5）O7（BEZN, x = 0, 0.05, 0.10, 0.15, 0.20, 0.25 and 0.30） ceramic was prepared via a solid phase reaction. The influence of Er3＋ doping on the microstructure and dielectric properties of the ceramic was investigated. The results show that when x〈0.15 （in mole）, the composition of sample appears an α-BZN structure at room temperature. However, the second phase can be observed when x≥0.15 （in mole）. The solution energy of Er^3＋ substituting for A site and B site was calculated based on the molecular dynamics simulation. It was found that Er^3＋ could be substituted for B site when x≥0.15 （in mole）. The Er^3＋ ion substitution can be incorporated into the Bi^3＋ site, and the density of BEZN ceramics decreases from 6.999 g/cm^3 to 6.680 g/cm^3 and the grain size of BEZN ceramics reduces when the Er^3＋ content increases. At 1 MHz, the maximum value of dielectric constant and the variation of dielectric constant in the relax temperature range decrease with the increase of Er^3＋ content.