Magnetic, Magnetocaloric, and Critical Exponent Properties of Layered Perovskite La 1.1 Bi 0.3 Sr 1.6 Mn 2 O 7 Prepared
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ORIGINAL PAPER
Magnetic, Magnetocaloric, and Critical Exponent Properties of Layered Perovskite La1.1Bi0.3Sr1.6Mn2O7 Prepared by Coprecipitation Method Y. Ounza 1 & M. Bouhbou 1 & M. Oubla 2 & M. Moutataouia 2 & M. Lamire 2 & E. K. Hlil 3 & H. Lassri 1 Received: 6 April 2020 / Accepted: 6 August 2020 # Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract The objective of the present work is to investigate the critical behavior and the magnetocaloric performance of the La1.1Bi0.3Sr1.6Mn2O7 double-layered perovskite, prepared by coprecipitation method, around the ferromagnetic (FM)-paramagnetic (PM) phase transition. Using Landau formalism, we have confirmed that the magnetic transition nature is of second-order with a Curie temperature of 340 K. The magnetic entropy values (−ΔSM) estimated by Landau theory are in conformity with those obtained using the classical Maxwell relation. The critical exponents have been obtained using various techniques such as modified Arrott plots (MAP), Kouvel-Fisher (KF), critical isotherm analysis (CIA), and Windom scaling relation (WSR). β, γ, and δ are close to the theoretical prediction of the mean-field model, indicating that the magnetic interactions are of a long range. Besides, an independent analysis of the critical behavior is presented in terms of the magnetocaloric effect supporting the validity of the mean-field approach. Keywords Double layered perovskite . Magnetocaloric effect . Critical behavior . Landau theory . Second order phase transition
1 Introduction Double-layered perovskite La2-2xSr1 + 2 xMn2O7 has attracted great scientific and technological attention due to their interesting electrical, ionic conductivity, luminescence, photocatalytic, and magnetic properties [1–5]. Furthermore, these systems have earned an intensifying interest not only for the colossal magnetoresistance (CMR) effect [6, 7] but also for their large magnetocaloric effect (MCE) [8, 9], one of the main defy preventing the actual use of these materials regardless of their interesting properties is that their Curie temperature TC is relatively too low [10, 11]. Therefore, in order to improve the magnetocaloric performance of La1.4Sr1.6Mn2O7 for magnetic refrigeration applications, it was imperative to
* M. Bouhbou [email protected] 1
University of Hassan II Casablanca, B.P. 5366 Mâarif, Route d’El Jadida, km-8, Casablanca, Morocco
2
University of Hassan II Casablanca, B.P. 5366 Mâarif, Route d’El Jadida, km-8, Casablanca, Morocco
3
Institut Néel, CNRS et Université Joseph Fourier, 166, F-38042 Grenoble Cedex 9, BP, France
increase its Curie temperature to nearby room temperature using appropriate substitutions. In this perspective, the substitution of La3+ by Bi3+ offers an advantage due to their close ionic radius, giving a magnetic material that possesses the desired TC; in our case, it is La1.1Bi0.3Sr1.6Mn2O7 [12]. The magnetic refrigeration technology is based on the magnetocaloric effect (MCE), where the MCE properties are analyzed through the magnet
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