Table-like magnetocaloric effect and large refrigerant capacity in Gd65Mn25Si10-Gd composite materials for near room temperature refrigeration

Abstract

Amorphous Gd65Mn25Si10 as well as crystalline Gd have technologically significant Curie temperature and large magnetic entropy change. Two types of composite materials Gd65Mn25Si10-Gd were fabricated: laminating Gd sheets and amorphous Gd65Mn25Si10 ribbons (multilayer composite) and hot pressing a mixture of amorphous Gd65Mn25Si10 thin ribbons, Gd particles and a small amount of Sn powders (bulk composite). A table-like magnetocaloric effect (MCE) in a wide, commercially useful, temperature span of 73 K (220 K-293 K) were observed in these composites. The values of full-width at half maximum of (−ΔSM) − T plots (ΔTFWHM) and enhanced refrigerant capacity (RC) for the multilayer and bulk composites are 212 K, 724 J/kg, and 248 K, 617 J/kg, respectively, for a field of 5 T. Large ΔTFWHM and RC values and the table-like (−ΔSM)max feature suggest that both multilayer and bulk Gd65Mn25Si10-Gd composites can meet the requirements of different magnetic refrigeration based on Ericsson-cycle.