Ferromagnetic Resonance Line Shapes in Permalloy Strips at Low Magnetic Fields

Spin rectification line shapes for ferromagnetic resonance in swept, low external bias fields differ significantly from widely investigated high-field resonant spectra. The anomaly in the low-field case may originate from magnetization rotation associated with magnetic anisotropy and demagnetization. The low-field, rectified voltage spectra are also sensitive to the relative phase and polarization of the microwave field. Ferromagnetic thin strips thus have the potential for use as polarization- and phase-resolved microwave detectors at low fields.