Spin wave spectra of non-magnetostrictive amorphous alloy films

The magnetic properties of a series of amorphous sputter deposited films were studied having the composition (Co1-xFexNi y)80 (Si1-zBz)20 with x≃0.1, y≃0.4, z≃0.6. The composition was chosen in order to obtain close to zero magnetostriction (λs≃0). Hysteresis measurements confirmed that these films are soft ferromagnetics. F.M.R. performed on films in the thickness range 0.1-0.6 μm shows well defined standing spin wave spectra corresponding to highly uniform samples: Modes with n≥2 follow a quadratic dispersion law with an excellent precision, the intensity of various spin wave modes decrease as 1/n2<I n<1/n4 and the corresponding linewidth ΔH n increases smoothly with n. A simple model is used to explain the origin of the pinning which is attributed to slight fluctuations of M s or Hi of the order of 40-100 Oe. The value of D as deduced from S.S.W. spectra is in excellent agreement with that deduced from static measurements of Ms=f(T).