Structural, microstructural and magnetocaloric properties of Gd1-xGax alloys

Structure, microstructure and magnetocaloric effect were investigated in Gd1-xGax (0.45 ≤ x ≤ 0.55) alloys. Phase identification and compositional analysis revealed that all these alloys consist of orthorhombic GdGa major phase with small fraction of tetragonal Gd3Ga2 and hexagonal GdGa2 secondary phases for Ga-lean and Ga-rich compositions respectively. The magnetic transition temperatures (TC) of the alloys were determined from AC susceptibility curves and it was found to be in the range of 181-186 K. Among these alloys, a maximum values of magnetic entropy change (ΔSM)max of 5.1 J kg−1-K, adiabatic temperature change (ΔTmax) of 4.6 K and refrigerant capacity (RC) of 644 J kg−1 were obtained in the x = 0.50 alloy.