Array anisotropy in structured thin film arrays: Influence on the magnetodynamics

The dynamic magnetic properties of soft-ferromagnetic thin film element arrays are strongly influenced by long range interelement magnetostatic interaction. In order to estimate the effective array dipolar field a quantitative model is presented, which is based on the superposition of stray fields that arise from the neighborhood of a reference element. Kittel's equation, that describes the magnetodynamics, is generalized for magnetically saturated arrays by additional array dipolar field terms. Measurements of the magnetodynamic response of quasi-saturated arrays with a rectangular base agree with theoretical predictions. Thus, our model allows the estimation of the frequency of the uniform precessional mode in mesoscopic thin film arrays with non-negligible magnetostatic interaction. ► Array anisotropy affects the ferromagnetic resonance frequency of thin film arrays. ► Effective array anisotropy fields are modelled. ► Effective array field terms add to demagnetizing terms in Kittel's equation. ► Theoretical and experimental effective array anisotropy fields agree.