Ferromagnetic resonance in amorphous (FeNi)80P10B10 alloys I. Alloys with high curie temperature

FMR measurements at room temperature on amorphous (Fe1–xNix)80P10B10 thin wires in the frequency range from 9.2 to 70 GHz are reported. In alloys with Curie temperatures well above the room temperature (x ≦ 0.7) saturation magnetic polarization Js, g-factor, effective anisotropy field HK and Landau-Lifshitz damping parameter λ are determined. The value of the spectroscopic splitting factor g = 2.09 is independent of composition x. For the alloys with x ≦ 0.4 the damping parameter λ is proportional to Js. Comparison with crystalline FeNi alloys shows that topological disorder has little effect on quenching of the orbital moment as well as on the relaxation mechanism in these amorphous alloys.