Magnetic properties of Co-based amorphous ribbon under cyclic heating and cooling

of the 57 Fe J isotope radiation for the investigated materials, measurement of each Mossbauer spectrum was carried out for about one week. The resonance effect turned out to be very low in spite of the significant extension of the measurement time period and big measurement statistics. Therefore, each measured Mossbauer spectrum was smoothed, which consisted in the decomposition of the experimental spectra to the convergent Fourier series and in discarding those harmonic components that have very small input to the total dispersion, by using the Parseval relationship [29,30]. Distributions of the magnetic hyperfine P(H) fields were determined for spectra smoothed in this way, by using the HFQS [31] program, employing the Hesse-Rubartsch method [32]. The P(H) distributions obtained are characterised by the following set of parameters: x - average value of the magnetic hyperfine field, x - average value of the isomeric shift, x DH - dispersion of the P(H) hyperfine fields distribution. The DH parameter characterizes the hyperfine P(H) magnetic fields’ distribution breadth and changes of its value are connected with fading or growth of the particular configurations of the vicinity of the 57-Fe isotope that occur in the thermal or mechanical treatment of the amorphous phase. The average values of the isomeric shift (in a smaller range) and the average values of the hyperfine magnetic field are sensitive to the closest atomic neighbourhood of the 57-Fe isotope and depend on the kind of atoms surrounding the Mossbauer isotope. Analysing changes of the DH and parameters gives grounds to draw conclusions pertaining to changes occurring in the closest neighbourhood of the Mossbauer isotope, featured by 57 Fe.