The Wide Operating Temperature Range in the Magnetocaloric Composite Formed by RMn2Si2 (R=Tm, Tb, and Dy) and HoCoSi Compounds

Abstract

RMn2Si2 (R = Tm, Dy, and Tb) and HoCoSi alloys, presenting multiple magnetic phase transitions (except for TmMn2Si2 and HoCoSi) and large magnetocaloric effect (MCE), were physically mixed to produce a composite magnetic refrigerant. The used concentration of each alloy was 0.1(TmMn2Si2) + 0.35(DyMn2Si2) + 0.4(TbMn2Si2) + 0.15(HoCoSi). X-ray diffraction and magnetization measurements were used to investigate the crystallographic and magnetic properties of the samples. The results indicate the maximum values of magnetic entropy change ( $$ -{\Delta S}_M^{max} $$ ) of ~ 4.6 J/kg K under magnetic field change (ΔH) of 50 kOe. A large table-like MCE was observed for the composite sample. The full width at half maximum of ΔSM peak (δTFWHM) values reaches ~ 60.4 K (ΔH = 20 kOe) and ~ 67.2 K (ΔH = 50 kOe), which correspond to a respective ΔSM peak broadening of 230% and 180% for the composite sample compared with each compound studied individually. Such property is important for a material to operate in an ideal Ericsson cycle.