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<p>In this study, we have investigated the effect of sodium doping on the structural, magnetic and magnetocaloric properties of <i>Pr</i><sub><i>0.55</i></sub><i>Sr</i><sub><i>0.45−x</i></sub><i>Na</i><sub><i>x</i></sub><i>MnO</i><sub><i>3</i></sub> manganites <i>(x = 0</i>,<i> 0.05</i>,<i> 0.1).</i> X-ray diffraction analysis revealed that all samples crystallize in an orthorhombic structure with the <i>Pbnm</i> space group. The magnetic study revealed a slight decrease in <i>T</i><sub><i>C</i></sub> from 304 <i>K</i> to 290 <i>K</i> with increasing sodium content, which can be attributed to a rise in <i>Mn</i><sup><i>4+</i></sup> concentration. The magnetocaloric effect (<i>MCE</i>) was theoretically investigated by using mean-field theory (<i>MFT</i>) in association with the Bean–Rodbell model (<i>BRM</i>) in order to take into account the structural disorder. The theoretical results were compared with experimental data computed by using the Maxwell relation. The excellent agreement between the two methods confirms the validity of <i>MFT</i> for modelling the magnetocaloric properties of <i>Pr</i><sub><i>0.55</i></sub><i>Sr</i><sub><i>0.45−x</i></sub><i>Na</i><sub><i>x</i></sub><i>MnO</i><sub><i>3</i></sub> samples. Magnetocaloric analysis demonstrated relative cooling power <i>(RCP)</i> values of 77.80, 78.80 and 79.35 <i>J/kg</i> under 2 <i>T</i> magnetic field for <i>x = 0</i>,<i> 0.05</i> and <i>0.1</i>, respectively, indicating the potential of these samples for magnetic refrigeration at room temperature. Furthermore, a theoretical composite based on the studied samples was proposed in order to enhance the <i>MCE</i> and optimize the performance for magnetic refrigeration.</p>

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Theoretical description of magnetocaloric effect in Pr0.55Sr0.45−xNaxMnO3 manganites based on mean-field theory

  • 期刊论文

  • 发表日期：

    2025年8月25日

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  • Wadii Mabrouki,
  • Akram Krichene,
  • Wahiba Boujelben

摘要

In this study, we have investigated the effect of sodium doping on the structural, magnetic and magnetocaloric properties of Pr0.55Sr0.45−xNaxMnO3 manganites (x = 0, 0.05, 0.1). X-ray diffraction analysis revealed that all samples crystallize in an orthorhombic structure with the Pbnm space group. The magnetic study revealed a slight decrease in TC from 304 K to 290 K with increasing sodium content, which can be attributed to a rise in Mn4+ concentration. The magnetocaloric effect (MCE) was theoretically investigated by using mean-field theory (MFT) in association with the Bean–Rodbell model (BRM) in order to take into account the structural disorder. The theoretical results were compared with experimental data computed by using the Maxwell relation. The excellent agreement between the two methods confirms the validity of MFT for modelling the magnetocaloric properties of Pr0.55Sr0.45−xNaxMnO3 samples. Magnetocaloric analysis demonstrated relative cooling power (RCP) values of 77.80, 78.80 and 79.35 J/kg under 2 T magnetic field for x = 0, 0.05 and 0.1, respectively, indicating the potential of these samples for magnetic refrigeration at room temperature. Furthermore, a theoretical composite based on the studied samples was proposed in order to enhance the MCE and optimize the performance for magnetic refrigeration.