Modeling of Magnetic and Magnetocaloric Properties by the Molecular Mean Field Theory in La 0.6 Sr 0.4 Mn 0.9 V 0.1 O 3
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ORIGINAL PAPER
Modeling of Magnetic and Magnetocaloric Properties by the Molecular Mean Field Theory in La0.6Sr0.4Mn0.9V0.1O3 Oxide M. Nasri 1,2 & J. Khelifi 1 & Sobhi Hcini 1 & Hussein Al Robei 3 & E. Dhahri 4 & Mohamed Lamjed Bouazizi 3 Received: 16 March 2020 / Accepted: 14 September 2020 # Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract Based on the mean-field theory, the magnetic and magnetocaloric behavior of La0.6Sr0.4Mn0.9V0.1O3 manganese oxide has been analyzed. The Bean-Rodbell equation of state presents a second-order magnetic phase transition with a η factor of η = 0.71. Using the experimental data of magnetization M (H, T), the molecular mean-field parameter is found to be λ1 = 2.19 T g emu−1. The Brillouin function makes it possible to determine the total angular moment J, the saturation magnetization MS, and the Lande factor g for La0.6Sr0.4Mn0.9V0.1O3 sample. We simulated the magnetization as a function of the magnetic field and the temperature by applying the mean-field theory, as well as the variation of the magnetic entropy change ΔSM(T). As observed, the simulated results close with experimental data. The magnetic entropy changes for the samples were also estimated by using the mean-field scaling theory, and the results show a difference between the theoretical and experimental values. Keywords Manganite . Magnetization . Magnetocaloric effect . Mean-field theory
1 Introduction The magnetic composite with high magnetocaloric effect (MCE) have been extensively studied experimentally and theoretically due to their large potential applications in magnetic refrigeration [1–3]. In order to understand the magnetic properties, the magnetocaloric effect (MCE) in various samples has been widely investigated. Magnetic refrigeration (MR) technology based on the MCE is more environmentally friendly, higher energy efficiency than classical gas compression/expansion refrigeration technology [1–3]. The discovery of a noticeably large MCE (change in entropy from 36 J kg−1 K−1 to 272 K for a change in magnetic field * J. Khelifi [email protected] 1
Faculty of Science and Technology of Sidi Bouzid, University Campus Agricultural City, University of Kairouan, 9100 Sidi Bouzid, Tunisia
2
Chemistry Department, College of Science, Jouf University, P.O. Box: 2014, Sakaka, Saudi Arabia
3
College of Engineering, Prince Sattam Bin Abdulaziz University, 655, Al Kharj 11942, Saudi Arabia
4
Laboratory of Applied Physics, Faculty of Sciences of Sfax, University of Sfax, PB 1171, 3000 Sfax, Tunisia
from 0 to 5 T) in Gd5 (Si1-xGex)4 has led to great research interest in environmentally friendly magnetic refrigeration [4, 5]. In low temperature applications in space technology, MCE materials are necessary not only for potential applications, for example, MR, but also for fundamental studies [6–8]. Weiss introduced that the molecular mean-field model in 1907 [8, 9] is used in magnetism due to its simplicity, but its limitations are well known, as by neglecting the correlations of fluctuat
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