  In this work, magnetization dynamics is studied in
superconductor/ferromagnet/superconductor three-layered films in a wide
frequency, field, and temperature ranges using the broad-band ferromagnetic
resonance measurement technique. It is shown that in presence of both
superconducting layers and of superconducting proximity at both
superconductor/ferromagnet interfaces a massive shift of the ferromagnetic
resonance to higher frequencies emerges. The phenomenon is robust and
essentially long-range: it has been observed for a set of samples with the
thickness of ferromagnetic layer in the range from tens up to hundreds of
nanometers. The resonance frequency shift is characterized by proximity-induced
magnetic anisotropies: by the positive in-plane uniaxial anisotropy and by the
drop of magnetization. The shift and the corresponding uniaxial anisotropy grow
with the thickness of the ferromagnetic layer. For instance, the anisotropy
reaches 0.27~T in experiment for a sample with 350~nm thick ferromagnetic
layer, and about 0.4~T in predictions, which makes it a ferromagnetic film
structure with the highest anisotropy and the highest natural resonance
frequency ever reported. Various scenarios for the superconductivity-induced
magnetic anisotropy are discussed. As a result, the origin of the phenomenon
remains unclear. Application of the proximity-induced anisotropies in
superconducting magnonics is proposed as a way for manipulations with a
spin-wave spectrum.
