S. Cohen, T.O. Sedgwick, et al.
MRS Proceedings 1983
Evidence for a vortex-glass phase is found from nonlinear current-voltage (I-V) characteristics measured on YBa2Cu3O7-δ thin films in high magnetic fields and at low temperatures. Well below the superconducting transition temperature the I-V curves are well described by E/J = ρ{variant}0 exp[-(J0/J)μ], with E the electric field and J the current density. The exponent μ is 0.19 ± 0.05 for low values of current density and μ = 0.94 ± 0.1 at high values. The results at low J are characteristic of a vortex glass and constitute the first direct evidence that the low-temperature state of a disordered superconductor is a vortex glass. The results are at variance with predictions from the theory of collective flux creep. Near the phase transition, both ρ{variant}0 and J0 exhibit critical behaviour. © 1993.
S. Cohen, T.O. Sedgwick, et al.
MRS Proceedings 1983
Mark W. Dowley
Solid State Communications
R.J. Gambino, N.R. Stemple, et al.
Journal of Physics and Chemistry of Solids
Sharee J. McNab, Richard J. Blaikie
Materials Research Society Symposium - Proceedings