Type-1.5 superconductivity in multigap superconductors.

The discovery of type-1.5 superconductivity in clean MgB2 single crystals (April 2009) has attracted much attention of researchers working in the field of superconductors. The importance of this finding is that the half-century used classification of superconductors into type-1 and type-2 is now found to be incomplete and a new type -1.5 should be added to the list. This new type of superconductivity means, first of all, new properties. Their deep investigation represents the purpose of the present project. The main difference in the behaviour of (now) three types of superconductors is manifested in their different responses to the applied magnetic field. The peculiarities of the responses are reflected in the arising vortex patterns and their evolution and dynamics with variations of applied field, temperature and current. Accordingly, the project is focused on the investigation of properties of the vortex matter in type-1.5 superconductors and the conditions for the realization of type-1.5 superconductivity in different materials. A primary condition for its realization is the existence of multiple superconducting bands. These conditions are also applicable to the iron pnictides which are nowadays the most intensively investigated superconducting materials in view of their promising applications. Besides homogeneous bulk superconductors, we also envisage the investigation of artificial sandwich structures made of type-1 and type-2 superconducting materials. The aim is to clarify how the proximity effect and the electromagnetic interaction between them can impose a type-1.5 behaviour in these structures.

Keywords:Type - 1.5, Vortex, SHPM, Superconductivity, Pnictide, MgB2

Disciplines:Other engineering and technology