摘要
利用交流互感法,在不同静磁场H_(dc)条件下,对块状烧结样品和粒度不同的粉末超导样品的交流磁化率X随温度T的变化进行了研究,某些样品的X～T特性曲线在起始转变温度下出现两个不同斜率的变化段;在不同静磁场H_(dc)条件下,对R-T特性曲线的低温拖尾段进行了研究,研究结果表明低场下,X～T和R～T的低温部分发生显著变化。对用块状烧结yBa_2Cu_3O_(7-δ)超导体制做的宏观“微桥”的临界电流I随静磁场H_(lc)的变化进行了研究,发现在H_(lc)=30O_e的低场下,I_e降低了约70～80%。并根据弱连接颗粒超导模型对上面结果作了定性解释。
Two sections with different slopes have been found in X-T and R-T curves in some YBa_2Cu_3O_(7-δ) superconductor samples. Their be- havior is remarkably influenced by the d.c.magnetic field. The chan- ge of the critical current Ic along with that of the magnetic field H_(dc) has been studied. It is found that when H_(dc)≈30Oe,Ic decreases almost by 70～80%. These Phenomena can be interpreted with the aid of a weak -link granular superconductor model.
