SANS MEASUREMENTS ON VORTICES IN SUPERCONDUCTORS. WHAT CAN WE LEARN?
Scattering of neutrons on the magnetic flux lines is extremely useful tool to study the “vortex matter”. The disapearence of the vortex lattice observed by SANS in High Temperature Superconductors provides the direct evidence for the melting transition of the Abrikosov lattice. The observation of the square lattice in Sr2RuO4 shed light on the symmetry of the order parameter in this unconventional superconductor.