La_（3－x）／2Ba_（（3－x）／2）Ca_xCu_3O_y超导体正电子寿

Positron Lifetime on La_((3-x)/2Ba_((3-x)/2)Ca_xCu_3O_y Superconductors

用ｘｔ子寿命谱方法研究Ｃａ局域替换Ｌａ（３－ｘ）／２Ｂａ（３－ｘ）／２ＣａｘＣｕ３Ｏｙ中的Ｌａ和Ｂａ引起的电子结构变化；并结合氧含量和转变温度的测量，分析了电子密度增加的原因．实验表明，随着Ｃａ含量的增加，体系正常态的正电子寿命明显减小，这表明正电子探测的电子密度增加．

Using the method of positron lifetime spectroscopy, the change of electronic structures caused by local substitution of Ca for La and Ba in La<,--.>l,Ba,,--.>/,Ca.Cu,O.material is studied. A decrease in the normal state lifetime of this system is experimentally observed with an increase in Ca concentration. It indicates an increase in electron densities detected by positron. With the measurement of oxygen content and critical temperature, the cause of an increase in electron densities have been studied.