Magnetic and magnetostrictive behavior of amorphous and nanocrystalline (by current annealing) Fe₈₆Zr₇B₆Cu₁ alloy

A reinforcement of the ferromagnetic character with applied tensile stress has been found in Fe₈₆Zr₇B₆Cu₁ amorphous alloy with a linear relationship between the change of the magnetization per unit stress. By annealing with electric current, an improvement of the magnetic softness of the alloy can be achieved in the range of current density of 50 to 75 Axmm^-2. Such an effect is connected to the presence of ultrafine grains of dimensions typically of nanometers. Results of the magnetostriction constant are also report edfor the as-quenched and nanocrystalline alloy which are interpreted in terms of surface and bulk contributions from α-Fe grains.