非化学配比对BaTiO_3缺陷及晶粒大小的影响

The Influence of Non Stoichiometry on the Defects and Grain Size of BaTiO 3

对原子分数为０．２５％的Ｌａ掺杂的具有不同Ｂａ和Ｔｉ原子数配比Ｒ的ＢａＴｉＯ３材料，通过正电子寿命测量和电镜观测，研究了Ｒ对材料缺陷及晶粒大小的影响．结果表明：Ｂａ过量明显地使材料中的Ｔｉ空位增多而使晶粒变小，Ｔｉ过量使材料中Ｂａ空位增多，同时使晶粒变大，但影响轻微．

The measurement of positron lifetime and observation by scanning electron microscopy (SEM) have been carried out for BaTiO 3 ceramics with different ratios R of Ba atomicity to Ti atomicity. Experimental results show that both the defect behavior and grain size of BaTiO 3 ceramics are influenced by non stoichiometery, i.e., by different R . In Ti rich samples, with an increase of 1/ R , both the Ba vacancy concentration and the grain size gradually increase. In Ba rich samples, as the R increases, the Ti vacancy concentration increases rapidly, but the grain size decreases significantly.