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 CaCu2 O8 ( ( Bi, Pb)-2212) single crystals, mag-netic measurements have been carried out. It is observed that the fishtail effect in (Bi, Pb)-2212 single crystal is depend-ent 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 do-ping. Additionally, at high temperature, the surface barrier is more important for magnetic properties.
参考文献
[1] | Y. P. Sun;W. H. Song;B. Zhao .Improved flux pinning and anomalous magnetization peak in heavily overdoped Bi_(2-x)Pb_(x)Sr_(2)CaCu_(2-y)Cr_(y)O_(8+δ) single crystals[J].Applied physics letters,2000(25):3795-3797. |
[2] | 刘洋,罗虹,冷祥,王智河,邱里,丁世英,林良真.不均匀超导体中的历史效应[J].低温物理学报,2002(04):241-247. |
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