  The recently discovered oxypnictide superconductor SmFeAs(O,F) is the most
attractive material among the Fe-based superconductors due to its highest
transition temperature of 56 K and potential for high-field performance. In
order to exploit this new material for superconducting applications, the
knowledge and understanding of its electro-magnetic properties are needed.
Recent success in fabricating epitaxial SmFeAs(O,F) thin films opens a great
opportunity to explore their transport properties. Here we report on a high
critical current density of over 10^5 A/cm^2 at 45 T and 4.2 K for both main
field orientations, feature favourable for high-field magnet applications.
Additionally, by investigating the pinning properties, we observed a
dimensional crossover between the superconducting coherence length and the FeAs
interlayer distance at 30-40 K, indicative of a possible intrinsic Josephson
junction in SmFeAs(O,F) at low temperatures that can be employed in electronics
applications such as a terahertz radiation source and a superconducting Qubit.
