Prediction of magnetocaloric effect using a phenomenological model in (x) La0.6Ca0.4MnO3/(1 − x) La0.6Sr0.4MnO3 composites

• Published in: Applied physics. A, Materials science & processing Vol. 125; no. 8; pp. 1 - 9
• Main Authors: Gharsallah, H., Jeddi, M., Bejar, M., Dhahri, E., Hlil, E. K.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.08.2019; Springer Nature B.V; Springer Verlag
• Subjects: Applied physics; Characterization and Evaluation of Materials; Composite materials; Condensed Matter; Condensed Matter Physics; Entropy; Fritting; Heat; Machines; Magnetic properties; Manufacturing; Materials Science; Nanotechnology; Optical and Electronic Materials; Physics; Physics and Astronomy; Predictions; Processes; Refrigeration; Scientific papers; Surfaces and Interfaces; Temperature dependence; Thin Films
• ISSN: 0947-8396; 1432-0630
• DOI: 10.1007/s00339-019-2851-y

This research paper presents a theoretical work on the magnetocaloric properties of (SC.4-2) composite obtained by mixing citric-gel La 0.6 Ca 0.4 MnO 3 (S0C1) and La 0.6 Sr 0.4 MnO 3 (S1C0), with mole fractions [0.875 (S0C1)/0.125 (S1C0)]. This mixture was then fritted at 900 °C. The magnetization of the composite goes in good agreement with the following relationship M ( S C . 4 - 2 ) = 0.865 × M ( S 0 C 1 ) + 0.135 × M ( S 1 C 0 ) , where (0.865, 0.135) are the corresponding weight fractions to mole fractions (0.875, 0.125) of parent compounds [(S0C1) (S1C0)]. Resting upon this equality, the magnetic entropy change and the specific heat of composite were predicted at a constant field and pressure. The variation of the magnetic entropy Δ S M and the heat capacity Δ C P , H as a function of temperature of the two parent compounds (S0C1) and (S1C0), with a phenomenological model, were obtained in our previous research work. The values of the maximum magnetic entropy change Δ S M m a x , full width at half-maximum δ T F W H M and relative cooling power (RCP), at several magnetic field variations, were determined. In addition to the S0C1 mother compound, the SC.4-2 composite displays the highest value of RCP, providing an estimate of the quantity of the heat transfer between the hot ( T hot ) and cold ( T cold ) ends during one refrigeration cycle. At a later stage, the study of the dependence on temperature of the magnetic entropy of ( x ) S0C1/(1 −  x ) S1C0 composites reveals that the optimum composition stands for x  = 0.4. Indeed, it gives comparable contributions of two parent compounds, leading to a practically uniform variation of entropy over a wide temperature range.