Magnetic imaging
The visualization of magnetic field patterns is a great tool for the investigations of condensed matter phenomena related to magnetism and superconductivity. In the case of superconductors, experiments can be carried out trapping magnetic field in the superconductor by cooling the material below its critical temperature while en external magnetic field is applied, or looking at the expulsion of magnetic field applied after the material was brought to the superconducting state (zero field cooling mode). From the magnetic field distribution it is possible to extract the critical current distribution in the sample. In our group we can perform magnetic imaging on different scales: the magneto-optical approach allows high resolution (400 nm) investigation on small samples and low applied fields, while the scanning-hall-probe-magnetometry technique gives access to cm scale samples with 50 μm resolution up to 5 T of applied field.
