ИСТИНА

In recent years Josephson junctions with ferromagnetic (F) barriers became quite desirable and actively developed devices in superconductive electronics. Among them are memory elements, improved RSFQ circuits and metamaterial structures. Still, characteristic voltage, ICRN, of most existing SFS junctions is much smaller than that of tunnel SIS devices. In this work we suggest SIsFS structures with complex interlayer consisting of tunnel barrier ‘I’, ferromagnetic layer ‘F’ and thin superconductor layer ‘s’ and study modes of operation of these devices. We show that these structures may achieve high ICRN and therefore are promising for the use as high-speed π junctions or memory elements [1-2]. We study in detail the pairing state in a thin middle superconducting film ‘s’ under proximity effect with ferromagnetic layer. The state of the ‘s’ film is controlled by inhomogeneities in ferromagnetic layer. We study the impact of different types of inhomogeneities including domain walls and normal phase inclusions on supercurrent transport in SIsFS structures. [1] T.I. Larkin, V.V. Bol'ginov, V.S. Stolyarov, V.V. Ryazanov, I.V. Vernik, S.K. Tolpygo, and O.A. Mukhanov, Appl. Phys. Lett. 100, 222601 (2012). [2] S.V. Bakurskiy, N.V. Klenov, I.I. Soloviev, M.Yu. Kupriyanov, and A.A. Golubov, Physical Review B 88, 144519 (2013).