Magnetic and magnetocaloric properties of Mn4−xFexGa2Sn

We investigate the magnetic and magnetocaloric properties of the new Mn4−xFexGa2Sn compounds (x = 0, 0.1, 0.4, 0.6, and 0.8) from DC magnetization measurements. These phases crystallize in a lacunar form of the η-Fe2−xGe type of structure (P63/mmc). They present a second-order paramagnetic to ferromagnetic transition whose temperature increases upon increasing the Fe content from TC = 317 K for x = 0 up to TC = 411 K for x = 0.8. The alloys with x ≤ 0.4 further exhibit another transition at lower temperature associated with a spin reorientation. The maximal magnetization and magnetic entropy change are found almost constant throughout the series close to ∼7.4 μB/f.u. and ∼12 mJ cm−3 K−1 (for μ0ΔH = 2.4 T), respectively. The magnetocaloric properties of Mn4−xFexGa2Sn are compared with those of previously investigated materials with high-temperature magnetic transition and their potential interest for high-temperature magnetocaloric applications is briefly discussed.