Effects of Sm-Doping on the Giant Magnetocaloric Effect in EuTiO3

Motivated by the need for viable replacements for cryogens such as liquid helium which are limited resources in high demand for research applications and increasingly used in industry, we have pursued the development of solid-state magnetic materials for low-temperature refrigeration applications in the liquid helium regime. To achieve this goal, samples of pure and samarium-doped europium titanate bulk materials were prepared by the sol-gel method. Our samples were confirmed to be phase pure and highly crystalline by X-ray diffraction and elemental purity of the samples was confirmed by energy dispersive spectroscopy. Our Sm0.15Eu0.85TiO3 (SETO) sample showed an increase in the peak magnetization and had no observed spin freezing as seen in EuTiO3 (ETO). Further, the magnetic entropy change at the Néel temperature around 5.7K and the Refrigeration Constant were increased for SETO compared to the ETO for the 5T field change. Improvement in the entropy change of the SETO was also observed to be large in the low field regime (0-1 T), where applications of magnetic materials for adiabatic demagnetization refrigeration are most practical.