Abstract
•The SEM measurements reveal a variable morphology of the grains according to the rate of substitution in Silver Ag.•The Rietveld analysis of X-ray diffractograms indicated that all the samples are two-phase.•The effect of the substitution of a divalent element such as strontium Sr2+ by a monovalent element such as silver Ag+ on the variation of the Mn-Mn distance between two adjacent MnO6 octahedra and also on the evolution of Mn-O-Mn and also on the overlap of manganese d orbitals and oxygen 2p orbitals.•The relative cooling power (RCP) is around 80.10 J/kg, 137 J/kg, 146.74 J/kg of X = 0, X = 0.1 f, X = 0.15 compounds for the 5T magnetic field.
We describe in this manuscript the effect of the substitution of a divalent element such as strontium Sr2+ by a monovalent element such as silver Ag+ on the variation of the Mn-Mn distance between two adjacent MnO6 octahedra and also on the evolution of Mn -O -Mn and also on the overlap of manganese d orbitals and oxygen 2p orbitals. then in this study, we synthesized by the solid-solid method the polycrystalline oxides La0.57Nd0.1Sr0.33-xAgxMnO3 (x = 0 and 0.15) LNSAMO.X-ray diffraction study shows that these compounds crystallize in the rhombohedral structure of space group R-3C and exhibit a second Mn3O4 phase of space group I 41 / amd. All the magnetization curves show a high temperature transition from a ferromagnetic state to a paramagnetic state near the Curie temperature (TC) and a second transition associated with the secondary phase Mn3O4. The Curie temperature decreases from 321 K to 307 K as the disorder increases. However, we have noticed that the substitution of strontium which is a magnetic element by non-magnetic silver causes the increase of the magnetization as well as the decrease of the temperature of Curie TC. When an external magnetic field μ0H = 5 T, we find that the values ofmagnetic entropy (ΔSMmax) are equal to 2.68, 4.55 and 5.08 J Kg 1 K 1, respectively, for x = 0.0, 0.1 and 0.15 samples. The relative cooling power (RCP) is around 80.10 J/kg, 137 J/kg,146.74 J/kg of X = 0, X = 0.1 f, X = 0.15 compounds for the 5T magnetic field. By basing the results of this work, we achieve that the controlled Ag doping adapts perfectly to the magnetic and Magnetocaloric characteristic of LNSMO Which perform a significant function in the realization of much potential applying of the compound in the field of approximately-room temperature magnetic refrigeration technology.
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