Transport phenomena of aligned ybco polycrystals near vortex-glass transition temperature in weak magnetic field

Abstract

Transport phenomena of aligned polycrystalline Y1Ba2Cu3O7−δ samples in weak magnetic fields near the vortex-glass transition temperature Tg have been studied. In YBCO polycrystal a fully superconducting state develops via an “intermediate phase”. The non-ohmic dissipation in this “intermediate phase” is examined in terms of both the thermal activated flux-flow (TAFF) model and vortex-glass transition model. Our experimental results in low magnetic fields can better be explained by a vortex glass transition model rather than a TAFF model. We have reinterpreted the non-ohmic dissipative region below Tc , i.e., the so-called “intermediate phase” in terms of a vortex-glass phase.