Large magnetocaloric effect in 0.25(La0.67Ca0.33MnO3 + La0.67Ca0.13Sr0.2Mn0.98Ni0.02O3) /0.5 La0.67Ca0.23Sr0.1Mn0.98Ni0.02O3 composite close to room temperature

Magnetic and magnetocaloric properties of a composite based on a mixture of several Sr and Ni doped La0.67Ca0.33MnO3 compounds with distinct magnetic features are investigated. All of the specimens were produced by the standard sol–gel method. The crystallographic quality and elemental composition were checked by X-ray diffraction and SEM analyses. The magnetic behavior of the composite can be tuned by the relative proportion of each parent compound. Distinct magnetic transition near room temperature are observed, leading to three different optimal values of the magnetic entropy change ΔSM in the presence of a magnetic field ranging between 0 and 5 T. We used the figure of merit such as temperature-averaged entropy change (TEC) for comparisons of magnetocaloric performance of the specimens. The relative cooling power RCP is improved by 45–58% as compared to the parent materials. Thus, the composite possesses an advantage in terms of high cooling power, which paves the way for a method to potentially improve the RCP of magnetocaloric materials.