Microstructure and magnetocaloric effects in partially amorphous Gd55Co15Al30―xSix alloys

Abstract In order to clarify the phase components and further improve the glass-forming ability of Gd 55 Co 15 Al 30 alloy, substitution of Al with Si was adopted. Although the X-ray powder diffraction experiment indicated an amorphous structure of the Gd 55 Co 15 Al 30− x Si x ( x  = 1, 2, 3) alloys, precipitation of crystalline Gd 2 Al phase was evident from the energy-dispersive spectroscopy, selected-area diffraction, and magnetization measurements. The magnetocaloric effect of Si substituted alloys is lower than that of Gd 52.5 Co 16.5 Al 31 alloy with a similar composition and full amorphous structure, which is ascribed to the presence of antiferromagnetic Gd 2 Al phase whose magnetic entropy change is lower.