Having succeeded in the fabrication of epitaxial superconducting ${\mathrm{LaFeAsO}}_{1-x}{\mathrm{F}}_x$ thin films we performed an extensive study of electrical transport properties. In the face of multiband superconductivity we can demonstrate that an anisotropic Ginzburg-Landau scaling of the angular dependent critical current densities can be adopted, although being originally developed for single band superconductors. In contrast with single band superconductors the mass anisotropy of ${\mathrm{LaFeAsO}}_{1-x}{\mathrm{F}}_x$ is temperature dependent. A very steep increase of the upper critical field and the irreversibility field can be observed at temperatures below 6 K, indicating that the band with the smaller gap is in the dirty limit. This temperature dependence can be theoretically described by two dominating bands responsible for superconductivity. A pinning force scaling provides insight into the prevalent pinning mechanism and can be specified in terms of the Kramer model.

• Received 8 December 2010

DOI:https://doi.org/10.1103/PhysRevLett.106.137001