Spin wave spectra of non-magnetostrictive amorphous alloy films

Abstract

The magnetic properties of a series of amorphous sputter deposited films were studied having the composition (Co_1−xFe_xNi_y)₈₀ (Si_1−zB_z)₂₀ with x?0.1, y?0.4, z?0.6. The composition was chosen in order to obtain close to zero magnetostriction (λ_s?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/n²n4 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 H_i 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 M_s=f(T).