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Theoretical and experimental studies of the magnetocaloric effect on lacunar compounds

Authors: M. Noumi, Y. Marouani, R. Dhahri, E. Dhahri, E.K. Hlil, B.F.O. Costa,

Ref.: J. Alloys Compd. 886, 157541 (2021)

Abstract: The physico-chemical properties of lacunar perovskite based materials have been analyzed with the study of the relations between the structure and the effect of defencies. Studies have been conducted on the effect of creating vacancies in lanthanum and sodium for the compound La0.8-x□xNa0.2-x□xMnO3 (x = 0, 0.05, 0.075) obtained by the sol-gel method followed by heat treatment at different temperatures and by X-ray diffraction in the surface. The magnetization measurements M (H, T), which were carried out using a magnetometer, proved that all studied compounds exhibited a second order reaction. The importance of -ΔSM induced by the weak magnetic field, introduce that the materials can be used for practical applications. Magnetic entropy change (ΔSM) values estimated by Landau theory and Hamad theory are close to those obtained using the classic Maxwell relation. The most important result is that our compound possesses relatively high values of magnetic entropy variation (ΔSM) and refrigeration capacity (RCP) which makes them promising candidates for magnetic refrigeration.

DOI: 10.1016/j.jallcom.2020.157541