Magnetic/structural diagram, chemical composition-dependent magnetocaloric effect in self-doped antipervoskite compounds Sn1−xCMn3+x (0≤x≤0.40)

The effects of Mn substitutions on the crystal structure, magnetic properties, and magnetocaloric effect (MCE) of antiperovskite Sn1−xCMn3+x (0≤x≤0.40) have been investigated detailedly. Both the Curie temperature (TC) and the magnetizations at 40 kOe decrease with increasing x firstly for x≤0.10, and then increase with increasing x further. The type of magnetic transition changes from first-order to second-order around x=0.10 with increasing x. Chemical composition-dependent MCE is also studied around TC. With increasing x, the maximal magnetic entropy changes decrease and the magnetic phase transitions broaden. Accordingly, the relative cooling power (RCP) increases with increasing x, reaching the largest values of ∼0.56 J/cm3 (∼75 J/kg) and ∼1.66 J/cm3 (∼221 J/kg) with the magnetic changes of 20 kOe and 48 kOe, respectively. Considering the large RCP, inexpensive, and innoxious raw materials, these serial samples Sn1−xCMn3+x are suggested to be potential room-temperature magnetic refrigerant materials.

▸ Around x=0.10, the type of FM–PM transition changes from first- to second-order. ▸ Curie temperature reduces firstly and then increase with increasing x. ▸ Magnetocaloric effect shows strong chemical composition-dependence. ▸ For x=0.30 and 0.40, the value of TC can exceed 300 K. ▸ Largest RCP can reach ∼0.56 J/cm3 and ∼1.66 J/cm3 under 20 and 48 kOe, respectively.