熔融织构(Nd-Eu-Gd)-Ba-Cu-O超导体的各向异性磁通跳跃及其不稳定性研究  

Flux jumps in textured (Nd_(0.33)Eu_(0.33)Gd_(0.33))Ba_2Cu_3O_(7-δ) superconductor with high content Gd-211 phase

作　　者：池长昀[1] 张金仓[1] 李领伟[1] 刘芬[1] 黎文峰[1] 敬超[1] 曹世勋[1] Miryala Muralidhar 姚忻[3] 

机构地区：[1]上海大学物理系,上海200436 [2]Superconductivity Research Laboratory(SRL),ISTEC,Japan [3]上海交通大学物理系,上海200436

出　　处：《物理学报》2005年第5期2307-2312,共6页Acta Physica Sinica

基　　金：国家自然科学基金 (批准号 :10 2 740 49);上海市教委曙光计划项目 (批准号 :0 3SG3 5 );上海市教委科技发展基金 (批准号 :0 2AK42 );上海市教委重点学科建设项目资助的课题 .~~

摘　　要：对c轴择优取向的熔融织构样品 (Nd0 33Eu0 33Gd0 33)Ba2 Cu3O7-δ(含Gd(2 11)相 )的磁通跳跃现象进行了系统研究 .结果表明 ,在外加磁场平行于样品c轴条件下 ,在 2到 3K的温度范围内明显观测到了部分磁通跳跃现象 ,而在5K及以上温区并未出现 .在磁场垂直于样品的c轴情况 ,在 2K到Tc 的整个温区都没有观察到磁通跳跃现象 .这种各向异性磁通跳跃现象可归因于各向异性钉扎力和几何退磁因子的结果 .随着温度的增加 ,磁通跳跃数目减少 ,且M(H)曲线的第三象限是磁通跳跃的最不稳定过程 .最后 ,研究了磁通跳跃对磁场扫描速率的依赖关系 ,并讨论了磁通蠕动对磁通跳跃的影响 .Flux jumps behavior in textured (Nd0.33Eu0.33Gd0.33 )Ba2Cu3O7-δ (with high content of Gd-211 phase) have been studied. With the magnetic field parallel to the c axis, partial flux jumps have been observed in the temperature range 2-3 K, and there were no jumps found above 5 K. When ab plane is parallel to the field direction, no flux jumps have been observed in the whole temperature range (from 2 K to Tc). The anisotropic flux instability may be due to the anisotropic pinning force and geometrical demagnetization factor. As the temperature increases, the number of flux jumps is decreased, and the third quadrant of M(H) curve is the most flux instability quadrant. Finally we have studied the magnetic field sweep rate dependence of flux jump, and discussed the influence of flux creep on flux jump.

关 键 词：超导体 熔融织构 各向异性 磁通跳跃 

分 类 号：O511[理学—低温物理] TM26[理学—物理]