6533b85dfe1ef96bd12bf19a

RESEARCH PRODUCT

Nondiverging vortex pinning barriers at low current densities across the putative elastic vortex-glass–vortex-liquid transition inYBa2Cu3O7−δfilms

subject

description

A detailed analysis of the electric field--current density $(E\ensuremath{-}J)$ characteristics of ${\mathrm{YBa}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7\ensuremath{-}\ensuremath{\delta}}$ films across the putative thermally induced elastic vortex-glass--vortex-liquid transition predicted by the $E(J)$ curve scaling reveals that the expected increase of the collective pinning barriers with decreasing J is cut off in the low-$J$ region, signaling a dissipation process which involves the plastic deformation of the vortex system. The temperature and magnetic field dependence of the pinning barriers at low J does not change across the scaling-predicted glass transition line. For the investigated magnetic field range (0.5--7 T), over a relatively large temperature interval, in ${\mathrm{YBa}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7\ensuremath{-}\ensuremath{\delta}}$ films there appears a continuous crossover in a pinned plastic vortex assembly, rather than a thermally induced elastic vortex-glass--vortex-liquid transition.