Features of Thermal Expansion and Magnetostructural Phase Diagram of the Multicomponent System (Tb,Y,Sm)Fe2

The paper presents the results of studying the thermal expansion of alloys of the multicomponent system (Tb $$_{{1-x}}$$ Yх)0.8Sm0.2Fe2 (where х is the substitution parameter) using tensometric and X-ray diffraction methods in a wide temperature range. A detailed study of the diffraction pattern was carried out at room temperature; splitting of the peaks was found for compositions with х = 0–0.4, indicating distortion of the initial cubic crystal lattice. Temperature dependences of the thermal expansion coefficient α(T) were plotted and analyzed. Features of thermal expansion in the region of magneto-phase transitions were discussed. A magnetostructural phase diagram of the alloy system (Tb $$_{{1-x}}$$ Yх)0.8Sm0.2Fe2 was constructed.