磁场下高温超导YBCO颗粒膜的非平衡微波响应

应用二维约瑟夫逊弱连接网络模型 ,讨论了磁场引起的二维超导体系中磁通“涡旋反涡旋”束缚对的激发问题 ,给出了自由涡旋分布 n( T,H )的分析表达式 ,对比 YBCO颗粒膜样品的非平衡微波响应测量数据发现 :两者具有相似的分布特征。该结果表明 ,高温超导颗粒膜的非平衡微波响应机制与磁通“涡旋反涡旋”束缚对的激发态可能存在某种内在联系。

Nonequilibrium Microwave Response in YBCO Granular Films under Magnetic Field

A two-dimensional Josephson junction array is proposed as a model system for granular YBCO films. Using this simplified model, we discussed the decoupling procedure of vortex-antivortex pairs by magnetic field, and analytically developed the temperature distribution of free vortices n(T,H) below T KT . As compared with the experimental results, we found that the temperature dependency of n(T,H) is similar to the behaviors of microwave response of granular YBCO films near K-T transition temperature. This similarity implies, to a certain extent, some intrinsic relationship between vortexantivortex decoupling and nonequilibtrium radiation response dissipation in the high T c superconducting granular films.