Phase Diagram and Magnetocaloric Effect of Mn₂Tb-Fe₂Tb System

Mn₂Tb-Fe₂Tb phase diagram was drawn, and the crystal structure and magnetocaloric effect of (Mn_1-xFe_x)₂Tb (x ≤ 0.5) compounds at the Mn-rich side were systematically studied. X-ray diffraction demonstrates that all these Laves phase compounds crystallize in the cubic MgCu₂-type structure. The Rietveld results of XRD shows the cell volume increases with Fe content. The influence of doping effect in (Mn_1-xFe_x)₂Tb (x ≤ 0.5) compounds on their magnetic and magnetocaloric properties for all solid solutions is presented. The Curie temperature (Tc) rises from 49 K (for x = 0.0) to 322 K (for x = 0.5), depending on Fe content significantly. Based on Landau's theory, the magnetization behavior and magnetic transition were analyzed. The magnetocaloric effect (MCE) of (Mn_1-xFe_x)₂Tb compounds is also discussed using the Maxwell relation, and the maximum magnetic entropy change (− ΔS_M^Max) approaches to 10 J kg⁻¹ K⁻¹ at x = 0 under a field ranging from 0 to 5 T. The best relative cooling power (RCP) reaches 535.03 J/kg (x = 0.1).