The effect of Si doping on the magnetic and magneto-thermal properties of Al rich Al_1.2-xSi_xFe₂B₂ intermetallic system

The Si-doped Al_1.2-xSi_xFe₂B₂ intermetallic system has been investigated by x-ray diffraction and dc magnetization measurements. The samples were prepared by arc-melting followed by drop-casting and annealing. X-ray diffraction patterns confirmed that all samples primarily exhibited the Cmmm-type orthorhombic crystal structure. A second-order ferromagnetic phase transition was observed near room temperature for all samples. Si doping significantly increased the magnetocaloric properties of the system. For a field change of 50 kOe, a peak magnetic entropy change of −7.4 J/kg K was observed in the system for x = 0.15. Refrigeration capacities up to 151 J/kg and 51 J/kg for field changes of 50 kOe and 20 kOe, respectively, were also observed. The results are discussed in terms of the phase purity of the samples.