LAUSR

Identifying the form of the superconducting order parameter in the Co-doped BaFe2As2 thin film is still an unsolved problem. With the Neumann boundary condition, we study the electromagnetic properties of this thin film based on the two-band Ginzburg–Landau theory. We get the analytic expressions for the upper critical field in arbitrary direction and the temperature dependence of critical supercurrent density through the film. Our theoretical results can fit the experimental data of upper critical field and critical supercurrent density well, which thus strongly suggests the Co-doped BaFe2As2 thin film as a two-gap [Formula: see text]-wave superconductor. Besides, a trijunction experiment is proposed to probe the [Formula: see text]++ or [Formula: see text] pairing symmetry in this material.