Giant demagnetization effects induced by superconducting films

We show that a ferromagnetic (F) slab with the in-plane magnetization sandwiched between two superconducting (S) films experiences strong demagnetization effect due to Meissner screening of stray magnetic field by superconductors. In extreme case transition S from normal state can switch factor 0 1 which is in sharp contrast S/F bilayers where such affects inside F film only slightly. The giant shown be qualitatively robust against decreasing thickness and may provide hint towards explanation anomalously large resonance frequency shift recently observed for S/F/S structures [I. A. Golovchanskiy, N. Abramov, V. S. Stolyarov, I. Chichkov, M. Silaev, Shchetinin, Golubov, Ryazanov, Ustinov, Yu. Kuprianov, Phys. Rev. Appl. 14, 024086 (2020)].