Bi－2223相T_（co）（t）的振荡和真空失超

The Oscillation Of T_(CO)(t)And Superconductivity Loss Of Bi-2223 Phase In Vacuum

用改变真空和换气氛的方法研究对Ｂｉ－２２２３相超导电性的影响时发现：１．Ｂｉ－２２２３相在真空条件下Ｔｃｏ随时间出发生衰减的余弦振荡；２．因真空脱氧能使原来的超导态Ｂｉ－２２２３相样品迅速失超。

A special sample cell with changable vacuum and;ltmosphcre is designed. Using this equipment, it is found that if the vacuum-deoxidation process lasts for several days there will be dapingoscillation of Bi-2223 phase's T(CO) with time (t), we have also found that initial superconducting state Bi-2223 phase sample (T(CO)=105K) keeping in He atmosphere is able to change into normalstate when the sample cell is suddenly pumped vacuum to 4×10(-3)t,No matter whether constantelectric current is 20mA or 2mA,this superconductivity loss is evident.The Bi-2223 sample in former superconductive Temperature range (<100K) can remain normal state even if the vacuum in the sample cell is increased and temperature decrease.