Damped magnetization oscillations in Ni-Fe thin films

Damped free oscillations of the magnetization have been clearly observed at the completion of 180° flux reversal along both the easy and the hard axis in Ni-Fe thin films. The frequency of these oscillations, as well as their damping, was studied as a function of the applied pulse field and compared to the results obtained by ferromagnetic resonance. Excellent agreement was found for oscillations excited by reversals along the hard axis when the frequency was measured after the amplitude had damped to small amplitudes. Along the easy axis, the free precession frequency was higher than the resonance frequency. An inconclusive attempt was made to associate the strength of the free precession signal with dispersion.