Study on measurement technique for magnetization dynamics of thin films

This paper describes our proposed measurement technique for the magnetization dynamics in thin films, which employs a microstripe line probe to detect ferromagnetic resonance (FMR) spectra for a film sample either with or without tensile stress. By measurement of FMR frequency shifts using Lorentzian fits to the FMR spectra for a film with and without tensile stress, saturation magnetostriction (λ_s) can be determined. The measured values were compared with those estimated by the optical cantilever method using the same samples in good agreement. At the same time, a Gilbert damping constant (α) was determined using both the FMR frequency and the FMR linewidth for the tensile stress free film. The results of the experiment demonstrate that our proposed measurement technique allows for more precise evaluation of magnetization dynamics by providing information on both α and λ_s simultaneously for an individual sample.