The critical current, Ic, of a superconducting wire is a technologically important parameter for high-temperature superconductivity engineering. In critical state models, it represents the maximum supercurrent a material can support before the onset of dissipation and damage. In the field of AC loss, Ic appears in in several equations based on a concept of current filling in a slab or strip geometry. However, the conventional approach to measure Ic for a given length of superconducting wire, relies on an arbitrary voltage measurement, typically chosen to be 1 uV cm-1. Recently, it has been demonstrated that the transport Ic of coated-conductor wire can also be observed from the evolution of the perpendicular magnetic field component near to the surface of the material. Here we expand on this work and describe a robust near-field criterion that defines current-filling within the tape, and the subsequent onset of significant flux-flow resistance. This now enables unambiguous values for the saturated critical current to be obtained from short-sample measurements of a transport superconducting tape using the perpendicular near-field method. This saturated critical current is directly equivalent to the critical state Ic for a superconducting strip.

Keywords: Critical current, Ic, Coated Conductors