Analysis of magnetization processes in nanocrystalline FeCoZr ferromagnets

Abstract By annealing an amorphous Fe 60 Co 30 Zr 10 alloy above the crystallization temperature, depending on the annealing temperature, different grain sizes can be produced. For small grain sizes, d ≤ 40 nm, the magnetic properties strongly depend on d . It is shown that H c , χ 0 and the Rayleigh constant α R follow a d 0 , d −6 and a d −17 power law, respectively, and can be described within the framework of the random anisotropy model (ram). The experimental relation between H c , χ 0 and α R shows good agreement with the statistical potential theory for domain wall movements. For larger grains d ≅ 60 nm we find reversible rotational magnetization processes.