摘要
本文报告了对低掺La的具有半导体化特性的BaTiO_5陶瓷的正电子寿命研究。实验结果发现,正电子湮没参量随掺La量的变化有着奇特的现象:寿命τ_1、τ_2随掺La量的增加是先变小后又变大,而强度Ia随掺La量的增加则是先变大后又变小,它们的转折点相同。本文认为,转折点以前的变化是由于Ba空位随掺La量的增加而增加造成的。为解释转折点以后的变化,引入了复合缺陷(Ba空位与La杂质离子形成的复合体)模型,并得到复合缺陷是不能捕获正电子的结果。
A study on positron lifetimes in lowly La-doped ceramic BaTiO3, which has semi-conduction, is reported. The experiment results show that the lifetimes TJ and τ2 decrease first and increase after, the intensity I2 increases first and decreases after with increasing amount of La, and these parameters turn at the same x value. The changes of τ1,τ2 and I2 below the turn result from increasing of Ba vacancies with increasing La. To explain the results a complex defect (Ba vacancy + La ion complex) model was proposed. The experimental results show that this complex defect does not trap positrons.
出处
《核技术》
CAS
CSCD
北大核心
1989年第3期153-156,共4页
Nuclear Techniques
