Y_（1－x）Pr_xBa_2Cu_3O_（7－δ）超导体正常态异常的正电子湮没  

POSITRON ANNIHILATION STUDY OF NORMAL STATE ANOMALY IN Y_(1-x)Pr_xBa_2Cu_3O_(7-δ)

作　　者：勾振辉[1] 陈烽[1] 郑胜男[1] 朱升云[1] 赵忠贤[1] 

机构地区：[1]中国原子能科学研究院,中国科学院物理所

出　　处：《低温物理学报》1995年第1期48-51,共4页Low Temperature Physical Letters

摘　　要：在７７—３００Ｋ温度范围内用正电子湮没方法测量了Ｙ１－ｘＰｒｘＢａ２Ｃｕ３Ｏ７－δ（ｘ＝０．２，０．１，０．０）三个超导样品中正电子湮没寿命随温度的变化，细致地研究了正常志异常现象．Ｘ为０．０和０．１的二个样品分别在较Ｔｃ高４０Ｋ和３０Ｋ处观察到了正常态异常现象ｘ＝０．２样品（Ｔｃ＜８０Ｋ）没有观察到正常态异常现象．实验观察到的正常态异常现象可能是发生超导转变的前奏，由结构不稳定产生的类相交所致．Abstract The temperature dependence of the positron annihilation lifetime in high quality, Single Phased Y1-xPrxBa2Cu3O7-δhas been measured from 77 to 300K for a better understanding of the origin of the normal Stte anomaly observed in high Tc superconductivity Studies. The normal state anomaly bas ben detected around 30 or 40 K above Tc for the samples with x= 0. 0 and 0. 1,but, not found for the sample of X=0. 2 with Tc lower than 80K. The experimental results demonstrate that the Phase-lice transition caned by the structural instability results in the observed normal state anomaly which may be the precursor of high Tc superconductivity.

关 键 词：超导体 正常态异常 正电子湮没 YPBCO 

分 类 号：TM262[一般工业技术—材料科学与工程] O511.1[电气工程—电工理论与新技术]