Josephson plasma emission in the high temperature superconductor superlattice

约瑟夫森等离子体共振是探测层状超导体涡旋态的有力手段，使我们能够定量地确定层间约瑟夫森耦合。本文测量了在各向异性的Bi_2Sr_2CaCu_2O_（8+6）中，涡旋晶格熔化到液相中时，约瑟夫森耦合的变化。我们发现，当穿过熔化线时，约瑟夫森耦合强度发生了显著的变化。结果表明，涡旋晶格经历了从三维晶格到解耦的饼状气体的转变。我们还研究了重离子辐照的影响。我们发现，柱状缺陷的引入改变了约瑟夫森耦合显着。解耦饼与磁场耦合的耦合跃迁。这种转变几乎发生在匹配场的三分之一。通过对共振态的详细分析，定量计算了pancekes分子沿着c轴的关联长度。

Josephson plasma resonance is a powerful means to probe the vortex state of layered superconductors, enabling us to determine the interlayer Josephson coupling quantitatively. In this research projest, we have measured how the Josephson coupling changes when the vortex lattice melts into the liquid in highly anisotropic Bi_2Sr_2CaCu_2O_<8+6>. We showed that the Josephson coupling strength changes dramatically when going accross the melting line. This result shows that the vortex lattice undergoes the transition from the three dimentional lattice to the decoupled pancake gas. We also studied the effect of the heavy-ion-irradiation. We showed that the introduction of the columnar defects changes the Josephson coupling dramatically. The coupling transition in which the decoupled pancakes couple with magnetic field. This transition occurs almost one-third of the matching field. We calculated the correlation length of the pancekes along the c-axis quantitatively from the detailed analysis of the resonance.