Iron-based superconductors at high magnetic fields

An overview of the behavior of Fe-based superconductors (FBSs) in magnetic fields is given with the emphasis on the materials features important for pinning of vortices, critical current densities, melting of the vortex structures and the upper critical fields. We also discuss how the multiband electronic structure of FBSs can result in extremely high upper critical fields tunable by doping or in the Fulde–Ferrel–Larkin–Ovchinnikov inhomogeneous state at high fields and low temperatures.