Magnetic phase transformations and hyperfine interactions in a multicomponent system alloys (Ho$_{1-x}$Y$_x$)$_{0.8}$Sm$_{0.2}$Fe$_2$ (0 $\le x\le$ 1)

This paper presents the results of the study of structural and magnetic properties, as well as hyperfine interactions in a multicomponent system alloys (Ho$_{1-x}$Y$_x$)$_{0.8}$Sm$_{0.2}$Fe$_2$, where $x$ = 0, 0.2, 0.4, 0.6, 0.8, 1.0. It is established that all the obtained alloys are single-phase and possess atomic-crystalline structure of cubic symmetry of the type of Laves C15 phase. For alloys of the system (Ho$_{1-x}$Y$_x$)$_{0.8}$Sm$_{0.2}$Fe$_2$ the values of Curie temperatures, saturation magnetisation $\sigma_s$ have been determined, the values of magnetic moment coming to the iron atom $\mu_\mathrm{Fe}$ have been calculated. The studies of the Mössbauer effect on $^{57}$Fe nuclei at room temperature have been carried out. The values of hyperfine parameters of Mössbauer spectra for all alloys of the system (Ho$_{1-x}$Y$_x$)$_{0.8}$Sm$_{0.2}$Fe$_2$ have been determined. The dependences of structural and magnetic parameters on the concentration of yttrium (a non-magnetic analogue of rare-earth elements) have been analysed and the features related to magnetic phase transformations in the studied system have been revealed.