Impact of synthesis routes on normal and inverse magnetocaloric effects and critical behaviour in the charge-ordered Pr0.5Sr0.5MnO3 manganite

A. Sakka; R. M’nassri; S. Tarhouni; W. Cheikhrouhou-Koubaa; N. Chniba-Boudjada; M. Oumezzine; A. Cheikhrouhou

doi:10.1140/epjp/i2019-12615-1

2022 Impact factor 3.4

EPJ PLUS - Condensed Matter and Complex Systems

Eur. Phys. J. Plus (2019) 134: 216
https://doi.org/10.1140/epjp/i2019-12615-1

Regular Article

Impact of synthesis routes on normal and inverse magnetocaloric effects and critical behaviour in the charge-ordered Pr_0.5Sr_0.5MnO₃ manganite

A. Sakka¹, R. M’nassri²^*, S. Tarhouni³, W. Cheikhrouhou-Koubaa³, N. Chniba-Boudjada⁴, M. Oumezzine¹ and A. Cheikhrouhou³

¹ Laboratoire de Physico-Chimie des Matériaux, Département de Physique, Faculté des Sciences de Monastir 5019, Université de Monastir, Monastir, Tunisia
² Unité de recherche Matériaux Avancés et Nanotechnologies (URMAN), Institut Supérieur des Sciences Appliquées et de Technologie de Kasserine, Kairouan University, BP 471, 1200, Kasserine, Tunisia
³ LT2S Lab, Digital Research Centre of Sfax, Sfax Technopark, BP 275, 3021, Sakiet-Ezzit, Tunisia
⁴ Institut NEEL, B.P. 166, 38042, Grenoble Cedex 9, France

^* e-mail: rafik_mnassri@yahoo.fr

Received: 9 October 2018
Accepted: 1 March 2019
Published online: 22 May 2019

Abstract

We investigated the effect of both synthesis routes on the physical properties of charge-ordered Pr_0.5Sr_0.5MnO₃ (PSMO) manganites. The samples are prepared by the solid-state reaction (SSR) and the modified sol-gel (SG) method. X-ray diffraction (XRD), SEM and magnetic measurement are used to study the structural, morphological, magnetic, magnetocaloric effect and the critical behaviour of our manganites. XRD studies confirmed the single phase orthorhombic formation of PSMO. Both compounds undergo two successive magnetic phase transitions with the variation of temperature: a paramagnetic (PM)-to-ferromagnetic (FM) transition around and 243K followed by an FM-to-antiferromagnetic charge-ordered transition at and 159K for the SG and SSR methods, respectively. Moreover, Banerjee's criteria, Landau analysis and universal curves of phase transitions are also studied to access the magnetic ordering of the PM-FM transition in the samples and confirmed the second-order character. Critical exponents associated with the ferromagnetic phase transition are analyzed and found to be inconsistent with any known universality class. Important magnetic entropy changes and the relative cooling power (RCP) were observed in the sample synthesized through the solid state method as compared to the sol-gel-synthesized sample. The PSMO compounds show both negative ( J/kgK for SSR and -1.1 for SG) as well as positive ( J/kgK for SSR and +1.52 for SG) magnetocaloric effects under a 2T field at ferromagnetic and charge order transitions, respectively. This feature of successive inverse and normal MCEs in Pr_0.5Sr_0.5MnO₃ are suggested to be applied in some magnetic refrigerators with special designs and functions.