Long-range inverse proximity effect in superconductor-ferromagnet structures
The spread of the Cooper pairs into the ferromagnet in proximity coupled superconductor - ferromagnet (SF) structures is shown to cause a strong inverse electrodynamic phenomenon, namely, the long-range spread of the magnetic field from the ferromagnet to the superconductor. Contrary to the previously investigated inverse proximity effect resulting from the spin polarization of superconducting surface layer, the characteristic length of the above inverse electrodynamic effect is of the order of the London penetration depth. The corresponding spontaneous currents generating this long-range magnetic field appear even in the absence of the stray field of the ferromagnet in the non-superconducting state and can naturally explain the puzzling experimental data on the long-range magnetism arising in V/Fe and Au/Nb/ferromagnet structures.