Magnetic domain compensation effect on the magneto-dynamic response of ferromagnetic elements

Tuning ferromagnetic resonance frequencies in soft ferromagnetic films relies on the possibility to tailor the uniaxial anisotropy of the film material. A systematic change of anisotropy field, being the solely changing material property, was achieved by preparing Ni81Fe19/Co60Fe20B20 multilayers. We show that in patterned films deviations from the regular Landau domain pattern occur, which compensate magnetic anisotropy effects and thereby lead to a precessional frequency independent of anisotropy. The results manifest the significance of even small changes in the magnetic domain structure over magnetic anisotropy adjustments for the optimization of the magneto-dynamic response in mesoscopic thin film elements.