Magnetic and magnetocaloric properties of melt-spun Gd x Ag100− x alloys

With the object of assessing their magnetocaloric properties, we have prepared GdxAg100−x alloys (x=50, 70, 75, 77.5, 80, 100) by melt spinning. The microstructures of the melt-spun ribbons were investigated by x-ray diffraction and transmission electron microscopy. Data from field- and temperature-dependent magnetization measurements were used to calculate the field-induced entropy change ΔS. The Gd-only ribbons are characterized by a single ΔS peak near 280 K. For the GdxAg100−x (70≤x≤80) materials ΔS contains another peak in the 100–120 K range which we ascribe to an amorphous, ferromagnetic Gd-Ag component. We find melt-spun Gd50Ag50 ribbons to consist primarily of crystalline GdAg (cubic CsCl structure), which is antiferromagnetic.