The scientific goal of this project is a detailed magneto-optical investigation of iron based superconductors. Magneto-Optical Imaging (MOI) is a versatile method to probe critical current density profiles in superconductors. The technique is well develop ed and is capable of addressing a plethora of questions around current distributions in superconductors. The study will be carried out on thin films of Co-doped BaFe2As2 (so called 1122 phase) and F-doped LaFeAsO (so called 1111 phase). After testing homo geneity and current density of the thin films by magneto-optical imaging, the following advanced chapters will be addressed:
1. Is there a thermo-magnetic instability in iron-based superconducting thin films that leads to dendritic flux avalanches?
2. Study of anisotropic pinning effects and intrinsic vortex channelling in vicinal films or along grain boundaries.
3. Study of transport properties of grain boundaries.
4. Study of the role of surface barriers and surface pinning effects in Fe/iron-ba sed superconducting bilayers.
These questions will help to gain deeper understanding of iron-based superconductors and related heterostructures. Using numerical models, a quantitative description of the observed effects will be elaborated. Transport cr itical current measurements will be performed and compared to the spatially resolved results of magneto optics.