Synergistic Magnetocaloric Effect in Composite Materials Based on Mixed Doped Lanthanum Manganites

In this work, the enhancement of the magnetocaloric effect by mixing different alkaline-earth-doped lanthanum manganites is reported. The sintering process of the mixed manganites promotes the unexpected presence of a strontium–calcium-co-doped lanthanum manganite phase that enhances the magnetocaloric properties of the composite. Consistent with this result, the composite shows three Curie temperatures at 263 K, 309 K, and 284 K, attributed to the three different phases found. The transition was identified as a second-order phase transition by the Arrott plots. A maximum entropy change of 11.66 J·(kg·K)⁻¹ was obtained for the composite at 18 kOe. It corresponds to a refrigeration cooling power of 484.98 J·kg⁻¹ near room temperature. The results demonstrated the synergistic contribution to the magnetocaloric properties of individual phases, enhancing the magnetocaloric effect by obtaining a composite.