Structural, magnetic and magnetocaloric properties of Ni54Mn14Ga27Fe5: the impact of annealing time

The structural, magnetic and magnetocaloric properties of Ni 54 Mn 14 Ga 27 Fe 5 Heusler alloy as a function of the annealing time have been investigated. The crystal structures have been characterized through multiphase Rietveld refinement of X-ray diffraction data. The alloys have cubic and the tetragonal structure with a mixed crystal phase at room temperature. In the magnetic measurements, the alloys exhibit the inter-martensitic and ferromagnetic–paramagnetic transition. The saturation magnetization values of the alloys decrease from 46.38 to 44.21 A m 2 kg - 1 as the annealing time is increased. The maximum magnetic entropy change is found to be as 2.8 Jkg - 1 K - 1 under 2 T magnetic field.