用正电子寿命谱研究铋系超导体的结构不稳定性  

Structural instability study of a Bi-based superconductorby the positron lifetime spectrum technique

作　　者：史志强[1] 卢亚锋[1] 

机构地区：[1]陕西师范大学

出　　处：《核技术》1998年第2期98-101,共4页Nuclear Techniques

基　　金：陕西省自然科学基金

摘　　要：室温下测量了铋系２２１２相超导体的正电子寿命参数随时间的变化，发现正电子寿命、平均寿命和体寿命都随着时间的延长而减小．直到１３０天以后各个正电子寿命参数才稳定。这说明氧化物超导体即使在室温下也是不稳定的。对由这种结构不稳定性引起的样品的电子结构。The variations of positron lifetimes with time at room temperature were measured for the Bi- based 2212 phase superconductor. lt is found that lifetimes and , intensity I1, mean lifetime and bulk lifetime all keep on decreasing for 130 days, and then remain roughly unchanged. This result confirms that the structure of oxide superconductors is instable even at room temperature. The decrease of the annihilation parameters with time is explained in terms of the intercalation of the excess oxygen in the region between the Bi-O layers. Possible correlations with the electron structure, oxygen content, hole density and transition temperature are also discussed.

关 键 词：铋系超导体 正电子寿命 结构不稳定性 

分 类 号：TM262.014[一般工业技术—材料科学与工程]