Time and Thermal Stability of Magnetic Properties in $Fe_{61}Co_{10}Y_{8}Nb_{1}B_{20}$ Bulk Amorphous Alloys

The paper presents studies of time and thermal stability of magnetic properties in $Fe_{61}Co_{10}Y_{8}Nb_{1}B_{20}$ bulk amorphous alloys. The investigated sample was prepared by suction-casting method in the form of plate. The structure was studied using X-ray diffractometry. It was found that alloy was amorphous in the as-cast state. The magnetic properties were determined using completely automated set up for measurement of susceptibility and its disaccommodation. The disaccommodation curve was decomposed into three elementary processes, each of them was described by Gaussian distribution of relaxation times. From fit of theoretical curve the peak temperature, intensity at peak temperature, average activation energies, distribution parameter and pre-exponential factor of the Arrhenius law were determined. The obtained results indicate that the disaccommodation phenomenon in studied samples is related with directional ordering of atom pairs near the free volumes.