Temperature-independent, constant E-J relation below ${\mathit{T}}_{\mathit{c}}$ in the current-induced resistive state of polycrystalline ${\mathrm{YBa}}_2$${\mathrm{Cu}}_3$${\mathrm{O}}_{7\mathrm{-}\mathit{x}}$

Restoration of the resistive state of bulk ${\mathrm{YBa}}_2$ ${\mathrm{Cu}}_3$ ${\mathrm{O}}_{7\mathrm{-}\mathit{x}}$ between 4.2 K and ${\mathit{T}}_{\mathit{c}}$ was investigated by transport measurements using J>${\mathit{J}}_{\mathit{c}}$. Unlike the low-${\mathit{T}}_{\mathit{c}}$ type-II superconductors, where restoration of the normal-state resistivity is obtained by exceeding ${\mathit{J}}_{\mathit{c}}$ by a fraction of ${\mathit{J}}_{\mathit{c}}$, a constant value of resistivity, which was several to many times smaller than that of the normal-state value, was obtained when ${\mathit{J}}_{\mathit{c}}$ was exceeded in bulk ${\mathrm{YBa}}_2$ ${\mathrm{Cu}}_3$ ${\mathrm{O}}_{7\mathrm{-}\mathit{x}}$ samples. This constant E-J slope remained constant up to ten times the transport ${\mathit{J}}_{\mathit{c}}$. Even more surprisingly, this value was constant for a given sample between 4.2 K and ${\mathit{T}}_{\mathit{c}}$. Near ${\mathit{T}}_{\mathit{c}}$ we observed two breaks in the E-J behavior, which we believe correspond to the inter- and intragrain ${\mathit{J}}_{\mathit{c}}$’s with the high ${\mathit{J}}_{\mathit{c}}$ in agreement with reported values obtained by magnetization. Microstructural results imply that the mechanism for the observed behavior may be weak-link related.