Critical current density in thin superconducting TaN film structures

The critical current density jC in thin TaN film single-bridge structures with different width from 60 nm to 8 μm has been studied in a wide temperature range from 4.2 K up to TC ≈ 10.2 K. At T → TC, the jC(T) curves of all bridges are described by the temperature dependence of the Ginzburg-Landau de-paring critical current in a temperature range increasing with the decrease in width of the bridges. However the zero-temperature value of the critical current density jCexp(0) used as fitting parameter decreases monotonically with the decrease in width of the bridges below ≈1 μm.