ANALYSIS OF MAGNETIZATION PROCESSES IN NANOCRYSTALLINE FECOZR FERROMAGNETS

By annealing an amorphous Fe60Co30Zr10 alloy above the crystallization temperature, depending on the annealing temperature, different grain sizes can be produced. For small grain sizes, d less-than-or-equal-to 40 nm, the magnetic properties strongly depend on d. It is shown that H(c), chi0 and the Rayleigh constant alpha(R) follow a d6, d-6 and a d-12 power law, respectively, and can be described within the framework of the random anisotropy model (ram). The experimental relation between H(c), chi0 and alpha(R) shows good agreement with the statistical potential theory for domain wall movements. For larger grains d is-approximately-equal-to 60 nm we find reversible rotational magnetization processes.