The magnetocaloric effect and hysteresis properties of melt-spun Gd5Si1.8Ge1.8Sn0.4 alloy

The master Gd5Si1.8Ge1.8Sn0.4 MCE alloy was prepared by the arc- melt method. The alloy was re- melted and melt- spun by single- roller melt spinning at different copper wheel speeds. Temperature- dependent x- ray diffraction ( XRD) and magnetic measurement confirm the first- order magnetic - crystallographic transition of as- cast Gd5Si1.8Ge1.8Sn0.4. From powder XRD results, the melt- spun technique preserves the monoclinic phase of Gd5Si1.8Ge1.8Sn0.4 but broadens the corresponding Bragg reflection which implies the smaller crystalline size of the melt- spun ribbons. For the spun ribbons, the refrigerant capacity ( RC) is comparable to that of the as- prepared Gd5Si1.8Ge1.8Sn0.4. The thermal (similar to 9.2K) and magnetic hysteresis (similar to 62 J kg- 1 at 270 K) near TC of the as- cast alloy have been significantly reduced (similar to 4K and similar to 5.7 J kg(-1) to similar to 7.5 J kg(-1) for ribbons, respectively) with the help of the melt- spun technique. The low hysteresis and large RC values make the spun ribbons suitable for magnetic refrigeration application near room temperature.