Magnetocaloric effect in Ni47Mn40Sn13 alloy prepared by mechanical alloying

The paper reports on the structural, microstructural and magnetocaloric properties of Ni47Mn40Sn13 magnetic shape memory alloy prepared by mechanical alloying (MA) technique. AC magnetic susceptibility shows a phase transition from a paramagnetic to ferromagnetic state in the austenite phase (TCA~318K) and martensitic transition around 210 K, which is also confirmed by differential scanning calorimeter (DSC) analysis. The total entropy change, associated with the transformation is estimated to be about 10.5 J/kg K by DSC measurement. Maximum magnetic entropy change of 4.3 and 2.3 J/kg K were obtained in a field change of 2 T at martensitic and magnetic transitions, respectively. The alloy shows a refrigerant capacity (57 J/kg in a field change of 2 T) at the magnetic transition temperature, comparable to the values observed in Ni-Mn alloys prepared by conventional techniques such as arc-melting and melt spinning. This study indicates that the MA technique have a potential technique for the fabrication of magnetic shape memory alloys for magnetic refrigeration.