Nonlinear dynamic effects in micron-sized Permalloy lines and their influence on HF filter applications

A combined time- and frequency-domain study on the dynamic properties of Permalloy (Py) lines with different shape anisotropies on top of coplanar waveguides (CPWs) is presented. Results are compared to numerical simulations of the magnetization dynamics using a macrospin model. The resonance frequency of microstructured ferromagnetic Py lines is observed to depend on the pumping field amplitude. This nonlinear effect has to be taken into account if these devices are to be used as high-frequency filters.