Electrical and Computer Engineering Commons^™

Quantum Nucleation And Thermal-Activation Of Vortex Rings In High-Tc Superconductors, H. Jiang, A. Widom, Y. Huang, T. Yuan, C. Vittoria, D. B. Chrisey, J. S. Horwitz

Carmine Vittoria

Vortex-ring nucleation by thermal activation and quantum-tunneling processes in high-Tc superconductors is discussed. The nonlinear resistance scales as eν-(J/J)ν. Thermal activation yields a critical index of v = 1, while quantum tunneling (without normal current dissipation) yields a critical index of v = 2. Current-voltage characteristics were measured on both disordered (low-Jc), ordered (c axis normal to the film plane, high-Jc) Y-Ba-Cu-O films, and microbridges below Tc. The data were examined in terms of both thermal-activation and quantum-nucleation models. For the disordered films, the v = 1 scaling law is in reasonable agreement with data, while v = 2 scaling …