Magnetocaloric effect of Pr^sub 2^Fe^sub 17-x^Mn^sub x^ alloys

Polycrystalline Pr^sub 2^Fe^sub 17-x^Mn^sub x^ (x = 0, 1, and 2) alloys were studied by X-ray diffraction (XRD), heat capacity, ac susceptibility, and isothermal magnetization measurements. All the alloys adopt the rhombohedral TH2Zn^sub 17^-type structure. The Curie temperature increases from 283 K at x = 0 to 294 K at x = 1, and then decreases to 285 K at x = 2. The magnetic phase transition at the Curie temperature is a typical second-order paramagnetic-ferromagnetic transition. For an applied field change from 0 to 5 T, the maximum -ΔS ^sub M^ for Pr^sub 2^Fe^sub 17-x^Mn^sub x^ alloys with x = 0, 1, and 2 are 5.66, 5.07, and 4.31 J·kg^sup -1^·K^sup -1^, respectively. The refrigerant capacity (RC) values range from 458 to 364 J·kg ^sup -1^, which is about 70 %-89 % that of Gd. The large, near room temperature [Delta]S ^sub M^ and RC values, chemical stability, and a high performance-to-cost ratio make Pr^sub 2^Fe^sub 17-x^Mn^sub x^ alloys be selectable materials for room temperature magnetic refrigeration applications.[PUBLICATION ABSTRACT]