A comprehensive analysis of the processes limiting the magnetic and temperature dependences of the critical currents of $\mathrm{Y}{\mathrm{Ba}}_2{\mathrm{Cu}}_3{\mathrm{O}}_{7-x}$ coated conductors is presented. We conclude that an unexpected heterogeneous vortex matter associated with two interacting vortex species characterizes the flux dynamics in the $H\text{−}T$ space: The Abrikosov-Josephson vortices (AJVs) nucleated on the grain boundaries and the Abrikosov vortices (AVs) localized in the grains. A crossover field separating a plastic motion of strongly interacting AVs- and AJVs from an individual pinning regime of AJVs has been identified.

• Received 16 March 2006

DOI:https://doi.org/10.1103/PhysRevB.73.132508