Exploring the heat capacity and magnetocaloric behaviors of rare-earth based multicomponent (Ce_0.71Pr_0.07Nd_0.22)₂Fe_17‐xSi_x alloys

The rare–earth based multicomponent (Ce_0.71Pr_0.07Nd_0.22)₂Fe_17−xSi_x (x = 0–0.6) alloys were fabricated by conventional arc melting following the standard annealing and quenching processes. The prepared alloys were characterized by X-ray diffraction (XRD), backscattered scanning electron (BSE) microscope, energy dispersive X-ray (EDX) spectroscopy, magnetization, and heat capacity measurements. Combination of Rietveld refinement of XRD patterns, EDX/BSE analyses confirm the formation of stable rhombohedral Th₂Zn₁₇ type crystal structure with R-3 m space group in all studied samples. The investigated samples experience second-order phase transition as confirmed through phenomenological universal scaling analysis. The magnetic entropy change (−ΔS_M) and associated relative cooling power (RCP) values for all compositions were found in the range of 1.1–1.4 Jkg⁻¹K⁻¹ and 55–66 Jkg⁻¹ under magnetic field change (ΔH) of 0–1 T. The ΔS_M curves as a function of temperature exhibit a wide working temperature range (δT_FWHM) over 40 K for all studied compositions. The performance-cost ratio − ΔS_M/cost and RCP/cost values are estimated to be 0.1 JK⁻¹$⁻¹ and 5.0 J$⁻¹, respectively. In particular, a large adiabatic temperature change of 7.36 K and 8.09 K was achieved for x = 0.2 and x = 0.4, respectively, at low ΔH= 0–1 T. The better performance-cost ratio and good magnetocaloric properties with near-zero magnetic hysteresis loss may make these alloys promising candidates for magnetic refrigeration.