Contents lists available at ScienceDirect Ceramics International journal homepage: www.elsevier.com/locate/ceramint Effect of trivalent rare earth doping on magnetic and magnetocaloric properties of La 0.47 (Y,Eu) 0.2 Pb 0.33 MnO 3 manganites A. Ben Hassine a , A. Dhahri a, ⁎ , M.-L. Bouazizi b , M. Oumezzine a , E.K. Hlil c a Laboratory of Physical Chemistry of Materials, Department of Physics, Faculty of Sciences, University of Monastir, 5019, Tunisia b Mechanical Department, College of Engineering - Prince Sattam Bin Abdulaziz University, 655 AlKharj 11942, KSA, Saudi Arabia c Institute Néel, CNRS–University J. Fourier, BP166, 38042 Grenoble, France ARTICLE INFO Keywords: Manganite Magneto-caloric effect Magnetic entropy ABSTRACT The La 0.47 Ln 0.2 Pb 0.33 MnO 3 (Ln=Eu and Y) polycrystalline has been synthesized using the solid state reaction method at high temperature. The X-ray diffraction shows that the materials crystallized in the orthorhombic structure. Magnetization measurements versus temperature in a magnetic applied field of 0.05 T show that all our samples exhibit a paramagnetic–ferromagnetic transition with decreasing temperature. The value of the Curie temperatures are 275 K and 264 K for Ln=Eu and Y, respectively. The magnetic entropy change reaches a peak ΔS (− ) m max also decreases from 3.31 J/kg. K for Ln=Eu to 2.97 J/kg. K for Ln=Y, and the corresponding values of relative cooling power (RCP) reach 243.25 and 178.88 J/kg, under a magnetic field of 5 T. The results suggest that those polycrystalline could be useful for magnetic refrigeration in a broad temperature range. 1. Introduction Over many years, the perovskite manganites of the type Re 1-x A x MnO 3 (Re=trivalent rare–earth, A=divalent alkaline earth) have received much attention because of their colossal magnetoresis- tance (CMR) and magnetocaloric (MC) properties [1–3]. These proper- ties can be tuned by doping of some chemical elements into Re and/or A, Mn sites. These CMR and MCE properties are usually explained by the double exchange (DE) interaction between the trivalent (Mn 3+ ) and tetravalent (Mn 4+ ) ions [4]. It is believed that the magnetic refrigera- tion is a more energy efficient along with being an environmental, friendly technology when compared with the traditional gas compres- sion refrigeration technology [5]. To find an active magnetic refrigerant (AMR) working at room temperature, most researchers focus on the metal alloys. These refrigerants, e.g. Gd [6], Gd 5 (Si x Ge 1-x ) 4 [7], LaFeSi [8], undergoing the first-order magnetic transition, generally have large magnetic entropy changes(ΔS m ). It should be noticed that although the first-order transition is able to concentrate the MCE in a narrow temperature range producing large (ΔS m ), the relative cooling power (RCP) becomes small. Furthermore, material with a large MCE undergoing first order transition is always in a high magnetic field and has considerable hysteresis. Refrigerants of manganites undergoing second–order magnetic transition with a large MCE take a resurgence of interest given their low hysteresis, affluent meta-magnetic transis- tion and coupling between charge and lattice. Manganites could be one of the most promising candidates for magnetic refrigeration technol- ogy, for the low production cost, ease of Curie temperature (T C ) tenability, chemical stability, and a relatively high resistivity. These properties are known for reducing eddy-current heating [9]. The manganite La 0.67 Pb 0.33 MnO 3 is one of the extensively studied which undergoes a paramagnetic - ferromagnetic transition around T C =360 K and it shows a ( ΔS − m max ) of 4.26 J kg -1 .K -1 under μ 0 H=5 T [10]. The ferromagnetic transition of the La 0.67 A 0.33 MnO 3 can be brought down to room temperature either by the substitution of La 3+ using another isovalent lanthanide ions or by partial replacement of Mn ions by other transition metal ions such as Co, Fe, Al, Ti, etc [11–15]. From this point of view, the main objective of this study is to tune the T C from 360 K to near room temperature. We tried to investigate the effect of Eu and Y substitution on the magnetic and magnetocaloric properties of La 0.47 (Y, Eu) 0.2 Pb 0.33 MnO 3 polycrystalline samples with Mn 3+ /Mn 4+ constant fraction but within different average ionic radius of the A site <r A > as well as different values of variance σ 2 . 2. Experimental procedures Polycrystalline samples of nominal compositions La Ln Pb Mn Mn O 0.47 3+ 0.2 3+ 0.33 2+ 0.67 3+ 0.33 4+ 3 (Ln=Y and Eu) were synthesized by a conventional solid-state reaction method. Raw materials of Ln 2 O 3 , PbCO 3 and Mn 2 O 3 , of purities higher than 99% were weighed in stoichiometric amounts. The detailed preparation of the samples is http://dx.doi.org/10.1016/j.ceramint.2016.10.098 Received 30 September 2016; Received in revised form 14 October 2016; Accepted 15 October 2016 ⁎ Corresponding author. E-mail address: abdessalem_dhahri@yahoo.fr (A. Dhahri). Ceramics International xx (xxxx) xxxx–xxxx 0272-8842/ © 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved. Available online xxxx Please cite this article as: Hassine, A.B., Ceramics International (2016), http://dx.doi.org/10.1016/j.ceramint.2016.10.098