Enhancement of magnetocaloric properties around room temperature in (1-x)La0.7Ca0.25Sr0.05MnO3/xLa0.7Ca0.2Sr0.1MnO3 system (0 ≤ x ≤ 1)

Highlights: • The parent compounds were elaborated by solid-state reaction. • Continuous curves were investigated by the numerical calculations in (1-x)La_0.7Ca_0.25Sr_0.05MnO₃/xLa_0.7Ca_0.2Sr_0.1MnO₃ system. • The optimum magnetocaloric effect has been found for the composition with x = 0.5 In this paper, a profound study has been conducted on magnetocaloric effect in (1-x)La_0.7Ca_0.25Sr_0.05MnO₃/xLa_0.7Ca_0.2Sr_0.1MnO₃ composite system. The present research work reveals an especial agreement between the experimental results and the continuous curves investigated by the numerical calculations in a two phases composite system (1-x)La_0.7Ca_0.25Sr_0.05MnO₃/xLa_0.7Ca_0.2Sr_0.1MnO₃. This approach can be used to elaborate magnetic material with enhanced magnetocaloric properties. In addition, the ability to adjust the temperature transition near room temperature is revealed to be possible by the mixture of both individual phases La_0.7Ca_0.25Sr_0.05MnO₃ and La_0.7Ca_0.2Sr_0.1MnO₃. Our samples have been synthesized using the solid state reaction. Rietveld refinement of the X-ray diffraction patterns reveals the same orthorhombic structure with Pnma space group for both component manganites. Magnetization measurements versus temperature in a magnetic applied field of 0.05T show that all our samples exhibit a paramagnetic ferromagnetic transition with decreasing temperature. The Curie temperature T_C is found to be 282 K and 308 K for La_0.7Ca_0.25Sr_0.05MnO₃ and La_0.7Ca_0.2Sr_0.1MnO₃, respectively. Moreover, the magnetic entropy change and the Relative Cooling Power (RCP) values were estimated for the biphasic system (1-x)La_0.7Ca_0.25Sr_0.05MnO₃/xLa_0.7Ca_0.2Sr_0.1MnO₃ with 0 < x < 1. We have shown that the optimum magnetocaloric effect at μ₀H = 2T has been found for the composition with x = 0.5, which exhibits a table-like ΔS_M curve with a peak value slightly lowered and strongly expanded around room temperature when comparing with those of the parent compounds. Therefore, we provide that the obtained results will draw attention of research for the development of magnetic refrigeration devices.