The effect deficient of strontium on structural, magnetic and magnetocaloric properties of La0.57Nd0.1Sr0.33−xMnO3 (x=0.1 and 0.15) manganite

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We have investigated the effect of nominal strontium deficiency on the structure, magnetic and magnetocaloric properties of La0.57Nd0.1Sr0.33−xMnO3 (x=0.1 and 0.15), [LNS0.23MO and LNS0.18MO] manganese perovskites. The polycrystalline samples have been elaborated by the conventional ceramic method at 1673K. The refinement of the structure by the Rietveld method revealed that these compounds crystallize in a rhombohedral (R3¯C) perovskite structure. Magnetization as a function of temperature shows that these compounds exhibit a paramagnetic to ferromagnetic phase transition with decreasing temperature. The ferromagnetic transition temperature (TC) decreases from 339K for x=0.1 to nearly the room temperature 315K for x=0.15 with increasing nominal strontium content. A large magnetic entropy change|ΔSM|deduced from isothermal magnetization curves, has been observed in our samples with a peak centered around their respective TC. The maximum of the magnetic entropy change |ΔSMmax| in a magnetic field change of 5T is found to be 4.42, 4.36Jkg−1K−1 for x=0.10, 0.15 respectively. The field dependence of the magnetic entropy change is also analyzed showing the power law dependence, ΔSM∝Hnwhere n=0.684(1) for x=0.1 and n=0.714(4) for x=0.15 at their respective transition temperatures. Large relative cooling power value of 214Jkg−1 is obtained for La0.57Nd0.1Sr0.18MnO3 sample, at a field change of 5T. This relatively large value associated to a curie temperature of 315K make the present compound a promising candidate for magnetic refrigerators around room temperature.