Neutron irradiation effect on amorphous and nanocrystalline FeZrB(Cu) at low temperature

The microstructure and magnetic properties of the amorphous and nanocrystalline Fe87.5 −xZr6.5sB6Cux (x = 0, 1) were studied using Mossbauer spectroscopy at liquid nitrogen temperature. Low temperature measurement of Mossbauer spectra enables a good resolution of the components the sample consist of. Under these conditions effect of neutron irradiation is easily studied through changes of average value of hyperfine magnetic field, hyperfine field distribution and orientation of net magnetic moment. As-cast samples reveal the existence of inequivalent sites of Fe corresponding to broad six line spectra at 77 K. Changes in the orientation of net magnetic moment were observed after neutron irradiation. Considerable changes were observed in the amorphous rest of the nanocrystalline samples. After the neutron irradiation low and high field components are well separated. Field resolution increases towards the higher stage of crystallization. Deviations in a magnetic structure are supposed to be a consequence of changes in a short range order due to neutron irradiation.