Ripple Relaxation Times in Thin Magnetic Films

Basically two different models have been proposed to characterize the effect of ripple on magnetization reversal. One of them assumes a long ripple relaxation time compared to thin-film switching times, the other short. To determine which model best describes switching phenomena, a small-angle fallback experiment has been devised which detects the change of the ripple reaction torque due to ripple rearrangements. From these data, a ripple relaxation time of 1.1±0.2 nsec was found which was relatively independent of angular dispersion. A theoretical calculation was made similar to that by K. J. Harte except loss was included. Using typical thin-film values, a 1.3 nsec ripple relaxation time was obtained which is in good agreement with experimental data. Therefore, except for the initial high-speed rotational process, the fast-relaxation model should best describe noncoherent rotational-switching behavior.