Magnetic Dynamics Variation Induced by the Meissner Effect in Superconductor/Ferromagnet Heterostructures

Abstract

Magnetic dynamics in superconductor (S)/ferromagnet (F)/superconductor (S) heterostructures is a focal spot in spintronics, but its physical origin remains debated. In this study, we fabricated S/F/S and S/Pt/F/Pt/S heterostructures to explore the impact of S layers on the magnetization dynamics of the F layer. We found that the ferromagnetic resonance field of the F layer shifted to lower fields as the temperature declined below the superconducting critical temperature T_c. Additionally, the inhomogeneous linewidth μ₀ΔH₀ broadened below T_c. Despite the insertion of thick platinum layers to block spin currents at the S/F interface, the resonance field shift persisted. We hypothesize that these variations result from the Meissner effect, which causes the S layers to generate an additional spatially inhomogeneous magnetic field below T_c. This leads to observed resonance field shifts and μ₀ΔH₀ broadening. Our findings clarify the origins of superconductivity-induced resonance field shifts and may advance superconducting spintronic devices for information processing.