Interaction of Mesoscopic Magnetic Textures with Superconductors.

The fabrication and experimental study [1] of mesoscopic heterogeneous magnetic/superconducting systems together with recent theoretical predictions [2–4] open a new class of physical effects. Earlier two of us (I.F.L. and V.L.P.) proposed to separate superconductivity and magnetism in space employing the modern technique of nanofabrication [2]. The proximity effect which suppresses both order parameters can be easily avoided by growing insulator oxide layers between ferromagnetic (FM) and superconducting (SC) components. Inhomogeneous magnetization of the magnetic texture generates magnetic field penetrating into the superconductor. The magnetic field from the SC currents interacts with magnetic subsystem [3,4]. We have proposed different realizations of mesoscopic magneto-superconducting systems: arrays of magnetic dots on the top of a superconducting film [2], magnetic/superconducting bi-layers [3], magnetic nanorods embedded into a superconductor [4]. In the majority of proposed systems a magnetic texture interacts with the superconducting current. An inhomogeneous magnetization generates magnetic field outside the magnet. The magnetic field generates screening currents in superconductors which, in turn, change the magnetic field. The problem must be solved self-consistently . In this article we develop a general formalism for interacting inhomogeneous magnetization (texture) and superconductors in the London’s approximation. Employ