Enhancement of the magnetocaloric effect in the Lu2Fe17−xMnx system

Non-monotonic variation of the magnetocaloric effect (MCE) with a maximal value for the composition x=0.7x=0.7 has been observed in the Lu2Fe17−xMnx system by means of isothermal magnetic measurements. The Lu2Fe17−xMnx compounds with x=0x=0–0.5 are ferromagnets at low temperatures and antiferromagnets at high temperatures, with a near-constant Néel temperature TN∼278K. The temperature of the “ferromagnet–antiferromagnet” phase transition, ΘTΘT, increases rapidly with increasing content of Mn, and the compounds from the range x=0.7x=0.7–2 are ferromagnets only, with the practically unchanged Curie temperature, TC(0.7)=287K. Thus, first- and second-order magnetic transitions merge for the composition Lu2Fe16.3Mn0.7, where the associated entropy change |ΔSM||ΔSM| 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.