电流作用下YBCO颗粒膜的非平衡微波响应  

Nonequilibrium microwave response in YBCO granular films under electric current

作　　者：肖胜[1] 付华明[1] 刘石香[1] 徐克西[1] 

机构地区：[1]上海大学物理系,上海200436

出　　处：《苏州大学学报（自然科学版）》2002年第3期71-76,共6页Journal of Soochow University(Natural Science Edition)

基　　金：上海市教委基金资助项目

摘　　要：从二维Josephson弱连接网络模型出发 ,讨论了二维超导体系的磁通“涡旋 -反涡旋”束缚对的激发问题 ,给出了当I≈Ic 时 ,涡旋对之间最大能与最小能之差ΔE比较大 ,而当I≥Ic时 ,ΔE=0 ,这说明当外界电流大于临界电流时 ,磁通涡旋甚至可以在 0K下也能被激发 .并进一步讨论了涡旋在电流作用下的激发问题 ,给出了自由涡旋的密度分布n(I ,T)的温度分布图 .对比高温超导体的非平衡响应曲线图 ,发现两者具有相似的分布特征 .该结果表明 ,高温超导体的非平衡响应与磁通“涡旋 -反涡旋”The question of decoupling of vortex antivortex pairs in YBCO granular films was reported on the basis of the two dimensional Josephson junction arrays. It is observed that the potential barrier Δ E has very large valaus in the small current regine, but Δ E=0 and implies the vortex antivortex pairs can unbind even at zero temperature when the external current is larger than the critical current. We compare the curves of temperature distribution of free vortices n(I,T) with nonequilibrium microwave response of YBCO granular films, which shows that there are some intrinsic relationships between nonequilibrium response in the high TC superconductors and vortex-antivortex decoupling.

关 键 词：二维超导体系 非平衡响应 磁通涡旋 激发 

分 类 号：O511[理学—低温物理]