Magnetic properties of amorphous and nanocrystalline alloys based on iron

In the present paper, two amorphous alloys: Fe74Cu1Cr3Si13B9 and Fe74Cu1Zr3Si13B9 were studied by applying the following experimental techniques: magnetic permeability, coercive force, magnetic after-effect, Hall constant and electrical resistivity measurements. Structural changes in annealed samples have been examined by X-ray diffraction analysis and high-resolution electron microscopy technique. It has been shown that magnetic properties of the examined alloys can be significantly improved by applying a suitable thermal annealing causing formation of α-Fe(Si) nanocrystalline phase with grain size from the range 2–6 nm and/or annealing out of microvoids. It has been found that the temperature of 1-h optimisation annealing as well as the temperature of first stage of crystallisation process in the first approximation is proportional to the atomic radius of the alloying addition (Cr, Mo, Zr).