Enhancement of the magnetocaloric effect in the system

Non-monotonic variation of the magnetocaloric effect (MCE) with a maximal value for the composition x=0.7 has been observed in the Lu sub(2)Fe sub(17-x)Mn sub(x) system by means of isothermal magnetic measurements. The Lu sub(2)Fe sub(17-x)Mn sub(x) compounds with x=0-0.5 are ferromagnets at low temperatures and antiferromagnets at high temperatures, with a near-constant Neel temperature [MathML equation]. The temperature of the "ferromagnet-antiferromagnet" phase transition, [theta] sub(T), increases rapidly with increasing content of Mn, and the compounds from the range x=0.7-2 are ferromagnets only, with the practically unchanged Curie temperature, [MathML equation]. Thus, first- and second-order magnetic transitions merge for the composition Lu sub(2)Fe sub(16.3)Mn sub(0.7), where the associated entropy change Delta S sub(M) is 3.6 J/kg K at 300 K in a field of 5 T. This is a way of enhancing the MCE in such multicomponent systems.