Excellent magnetocaloric properties in RE₂Cu₂Cd (RE = Dy and Tm) compounds and its composite materials

The magnetic properties and magnetocaloric effect (MCE) of ternary intermetallic RE₂Cu₂Cd (RE = Dy and Tm) compounds and its composite materials have been investigated in detail. Both compounds undergo a paramagnetic to ferromagnetic transition at its own Curie temperatures of T_C ~ 48.5 and 15 K for Dy₂Cu₂Cd and Tm₂Cu₂Cd, respectively, giving rise to the large reversible MCE. An additionally magnetic transition can be observed around 16 K for Dy₂Cu₂Cd compound. The maximum values of magnetic entropy change (-ΔS_M^max) are estimated to be 17.0 and 20.8 J/kg K for Dy₂Cu₂Cd and Tm₂Cu₂Cd, for a magnetic field change of 0-70 kOe, respectively. A table-like MCE in a wide temperature range of 10-70 K and enhanced refrigerant capacity (RC) are achieved in the Dy₂Cu₂Cd - Tm₂Cu₂Cd composite materials. For a magnetic field change of 0-50 kOe, the maximum improvements of RC reach 32% and 153%, in comparison with that of individual compound Dy₂Cu₂Cd and Tm₂Cu₂Cd. The excellent MCE properties suggest the RE₂Cu₂Cd (RE = Dy and Tm) and its composite materials could be expected to have effective applications for low temperature magnetic refrigeration.