Structural, Magnetic and Magnetocaloric Effect of Gd₆(Mn_1−xFe_x)₂₃ Compounds

The influences of Mn/Fe ratio on the structural, magnetic and magnetocaloric properties of Gd₆(Mn_1−xFe_x)₂₃ (x = 0.0–0.5) compounds have been investigated by means of X-ray diffraction (XRD) and magnetic measurements. The XRD results show the compounds crystallize in the cubic Th₆Mn₂₃-type structure, and the lattice size decreases with the decrease in Mn/Fe ratio. Magnetic measurements show that the samples exhibit a second-order magnetic transition from T_C = 99 K for x = 0.3 down to T_C = 89 K for x = 0.4 and increase to 293 K for x = 0.5. The magnetization measured at 10 K decreases from 119 emu/g for x = 0.0 to 82 emu/g for x = 0.4, but the magnetization is 105 emu/g at x = 0.5. For an applied field from 0 to 5 T, the maximum values of magnetic entropy change (− ΔS_M) for Gd₆(Mn_1−xFe_x)₂₃ compounds with x = 0.3, 0.4 and 0.5 are 3.56 J/kg K, 3.77 J/kg K and 1.79 J/kg K, respectively. The properties of Gd₆(Mn_1−xFe_x)₂₃ compounds help to understand the exceptional physical characteristics and provide the information for seeking giant magnetocaloric materials.