(Bi,Pb)_2Sr_2CaCu_2O_y单晶的磁通钉扎研究  

FLUX PINNING STUDY ON A (Bi,Pb)_2Sr_2CaCu_2O_y SINGLE CRYSTAL

作　　者：张莉[1] 刘果红[1] 丁世英[2] 孙玉平[3] 朱雪斌[3] 

机构地区：[1]安徽建筑工业学院,数理系,合肥230022 [2]南京大学,物理系,南京210093 [3]中国科学院固体物理研究所,材料物理重点实验室,合肥230031

出　　处：《低温物理学报》2009年第3期216-220,共5页Low Temperature Physical Letters

基　　金：安徽建筑工业学院博士科研启动基金资助的课题~~

摘　　要：我们通过对重Pb掺杂的Bi-2212((Bi,Pb)-2212)单晶磁化性质的测量来研究磁通钉扎性能,发现样品中存在与温度有明显依赖关系的鱼尾效应,且此鱼尾效应不仅体现在磁滞洄线上,还体现在不同磁场下零场冷的M～T曲线的交叠上.同时我们采用非线性磁通蠕动模型,并考虑表面位垒和体钉扎的影响,运用数值模拟分析了样品的磁化性质,结果表明(Bi,Pb)-2212单晶的鱼尾效应源于重Pb掺杂导致样品各向异性的降低所引起的强的体钉扎效应,而高温的磁化性质主要取决于表面位垒的作用.To study the pinning mechanism in heavily Pb-doped Bi2 Sr2 CaCu2O8 （ （ Bi, Pb）-2212） single crystals, magnetic measurements have been carried out. It is observed that the fishtail effect in （Bi, Pb）-2212 single crystal is dependent on temperature, and it manifests itself both on a single magnetic hysteresis loop and on the crossover of ZFC M - T curves under different fields. The experimental results are analyzed through numerical simulation using non-linear flux creep model of cooperation effects of surface barrier and bulking pinning force. The results show that the fishtail effect in （ Bi, Pb）-2212 single crystal originates from stronger bulk pinning caused by anisotropy depression induced from heavily Pb doping. Additionally, at high temperature, the surface barrier is more important for magnetic properties.

关 键 词：(Bi Pb)-2212单晶 鱼尾效应 磁通钉扎 磁通蠕动 

分 类 号：O511[理学—低温物理] TN304.23[理学—物理]