Random Magnetic anisotropy and Ferromagnetic Resonance in nanosrystalline alloy Fe73.5CuNb3Si13.5B9

In the paper, we will present experimental results on the Fe73.5CuNb3Si13.5B9 ferromagnetic resonance (FMR) line width as a function of annealing conditions, as well as the annealing-temperature dependence of the crystallite size, coercive force, and the magnetic anisotropy field. We shall show the interrelationship of these quantities, demonstrate that these parameters are all traceable to the nanoparticle crystallization, and indicate how they can be examined by extending the random anisotropy theory. To obtain quantitative parameters of random magnetic anisotropy we investigate the magnetization curves approaching saturation. This technique allows one to quantitatively determine the local magnetic anisotropy field (H-a) and magnetic anisotropy correlation radius (R-e), as well as to estimate the averaged magnetic anisotropy field (<H-a>(L)) and ferromagnetic correlation radius (R-L).