Tl_2Ba_2Ca_2Cu_3O_y超导体低场钉扎力的性质

CHARACTERISTICS OF PINNING FORCE IN LOW FIELD FOR Tl_2Ba_2Ca_2Cu_3O_y SUPERCONDUCTOR

测量了Tl_2Ba_2Ca_2Cu_3O_y超导体多晶样品在不同外磁场和不同温度下的磁滞性质,利用临界态方程求出有效钉扎力随外磁场及温度的变化,有效钉扎力包括晶粒界面处及晶粒内的贡献,发现有效钉扎力有峰效应,峰位置随温度降低向较高磁场移动,峰效应被解释为两种钉扎机制产生的,即两种机制的贡献与外磁场的关系不同,还讨论与这些结果有关的问题。

By measuring magnetization curves of polycrystalline Tl2Ba2Ca2Cu8Oy superconductor, magnetitudes of the hysteresis against temperature T and applied field Ba have been obtained. Using the critical state equation, we have got an effective pinning force which varies with temperature and field and results from both contributions of winklinks and intragrain pinning. Peak effect of the effective pinning force has been found, and the peak moves to higher fields with temperature dropping. The peak effect is considered to be the results of two pinning mechanisms, which have different field relations. Finally, some discussions about the results are made.