Structure of induced currents in equilibrium superconducting states.

The proposed project is aimed at studying the structure of field-induced currents in the Meissner state (the primary objective) as well as in the mixed and filamentary equilibrium states of a type-II superconductor using a small-angle neutron scattering technique. As follows from a novel so-called micro-whirls model, the Meissner phase is filled with induced microscopic currents, which form a network of hexagonally ordered whirls parallel to the field H. We expect that the project will allow us to detect the structure of the induced currents and to measure the radius of the whirls and the London penetration depth. If successful, the project will open a new page in studies of superconductivity, in particular it will pave a way to measure microscopic parameters of superconductors, which are necessary for understanding of specifics of Cooper pairing in all superconducting materials.