Vortex glass phase transition in two-dimensional Bi₂Sr₂Ca₂Cu₃O 10+δ sub-microbridge

Abstract

Vortex dynamics is crucial to practical applications and to understand the nature of the mixed state for high Tc superconductors. Mechanically exfoliated ultra-thin single crystals provide an unique platform for exploring vortex physics in the two dimensional limit. Here, we systematically investigated current-voltage characteristics as functions of temperature and magnetic field in 2.5 unit cells single crystalline Bi2223 sub-microbridge. The nonlinear current-voltage characteristics are excellently described by the scaling theory for a quasi-two dimensional vortex glass phase transition and a phase diagram revealing the vortex glass and vortex liquid phase is drawn. The scaling parameter v is consistent with previous reports, while the critical exponent z is far smaller than that in most investigations. Moreover, the vortex glass transition temperature Tg of the present sample is higher than the reported Bi2223 epitaxial thin films and tapes. In addition, the pinning force density of our sample is calculated, which is stronger than that reported in Bi2223 epitaxial thin films and tapes. Our results indicate that high pinning force density may suppress the dynamical critical exponent z and enhance the vortex glass phase transition temperature, providing a new insight to the flux dynamics in cuprates.