Room temperature magnetocaloric effect in Mn1.25Fe1.75Ga Heusler alloys

A room temperature magnetocaloric material with composition Mn1.25Fe1.75Ga is reported in this paper. The as-synthesized melt-spun ribbons have the pure L21 cubic structure and a homogeneous microstructure with an average grain size of 6 μm and show a ferromagnetic to paramagnetic transition at 296 K. The change in entropy determined from the M versus H curves was found to be 3 J kg−1K−1 at 296 K and 3 T, which is good in comparison with the values of commonly used materials for magnetic refrigeration. However, in comparison with other materials, the room temperature magnetocaloric effect is obtained by tuning the composition of the parent alloy without the need of another heat treatment. This important result opens opportunities for magnetic refrigeration near room temperature.