2H-Nb_(0.9)Ta_(0.1)Se_2中磁通涡旋输运的标度行为

SCALING BEHAVIOURS OF VORTEX TRANSPORT IN 2H-Nb_( 0.9) Ta_( 0.1) Se_2

测量了 2H Nb0 .9Ta0 .1 Se2 单晶样品在不同电流下电压随磁场变化的曲线V(H) ,并从V(H)曲线得到V(I)数据 .使用标度关系V =α(I-Ic)β进行了拟合 ,得到了临界电流随磁场Ic(H)和微分电阻随磁场Rd 的变化关系 .在微分电阻随磁场变化的曲线中 ,电流较大时 ,靠近上临界磁场Hc2 附近出现一个强峰 ,而在低电流下 ,该峰消失 .同时在临界电流峰效应区的起始处出现一小峰 .实验结果表明掺Ta后 ,涡旋体系的动力学特性发生了显著的变化 .

The field dependence of voltage V(H) in a 2H-Nb0.9Ta0.1Se2 single crystal at various currents was measured and converted to current-voltage data V(I). Then the scaling law V = alpha (I- I-c)(beta) was applied to extract the critical current I-c(H) and differential resistance R-d( H). The results show a peak on the differential resistance vs. H curve near H-c2 when the applied current is high, but for a lower current it appears near the onset of peak effect region. This indicates that the new types of pinning centers generated by doped Ta. significantly alter the dynamic properties of the vortex system.