Methods for determination of response times of magnetic head materials

Measurements of magnetization response times in thin-film Permalloy are made by both electrical and optical methods. The electrical method measures the inductive voltage generated in a waveguide by the changing magnetization. The optical technique uses standard pump-probe sampling methods combined with the second-harmonic magneto-optic Kerr effect to directly measure magnetization angle as a function of time. Results of these measurements for a 75 nm thick Permalloy film are in good qualitative agreement.