Magnetic and magnetocaloric properties of Fe5−xMnxSn3

We investigate the crystal, magnetic and magnetocaloric properties of the Fe5−xMnxSn3 series (0≤x≤5) from X-ray diffraction and DC magnetization experiments. The alloys crystallize with the lacunar Ni2In type of structure (P 63/mmc). The diffraction patterns of the richer Fe alloys (x≤2) contain tiny superstructure lines due to ordering of T atoms and vacancies within the partially filed 2d position. The Curie temperatures decrease in a non-monotonous manner with the Mn content from 544 K in Fe5Sn3 down to 190 K in Fe1Mn4Sn5, before increasing again up to 219 K in Mn5Sn3. While most of the alloys behave as simple ferromagnets, low-field thermomagnetization data show that the Fe5−xMnxSn3 alloys with intermediate compositions (x=2.5 and 3) undergo two close ferromagnetic-like transitions. The magnetocaloric effect is of moderate magnitude (~1 J kg−1 K−1 for μ0ΔH=2T). The results are compared with previously published data and briefly discussed in view of potential high-temperature magnetocaloric applications.