Magnetocaloric effect in Tb2O3 and Dy2O3 nanoparticles at cryogenic temperatures

Abstract

Magnetic refrigeration is a cooling technology based on the magnetocaloric effect, which has greater energy efficiency than conventional refrigeration, and has attracted much attention for low and room temperature cooling applications. Here, we report magnetocaloric effects at cryogenic temperatures in nanostructured rare earth oxides prepared by rare earth nitride formation and successive oxidation that guarantees chemical stabilities and finer particle sizes of rare earth oxide nanoparticles. Tb2O3 and Dy2O3 rare earth oxides with a cubic structure were prepared that undergo a second-order magnetic transition at Néel temperatures of 8 K and 4 K, respectively. Magnetic entropy changes (−ΔSM) were 6.6 and 18.2 J/kg K, respectively, at an applied magnetic field of 6 T.