Structural, magnetic and magnetocaloric properties of Ag-doped Pr_0.5Sr_0.5-xAg_xMnO₃ manganites (0.0≤x≤0.4)

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• 作者：S. Tarhouni^a ; ^b ; ^{tarhouni.sabrine@ymail.com" class="auth_mail" title="E-mail the corresponding author} ; A. Mleiki^a ; ^b ; I. Chaaba^a ; H. Ben Khelifa^a ; ^b ; W. Cheikhrouhou-Koubaa^a ; ^b ; M. Koubaa^a ; A. Cheikhrouhou^a ; E.K. Hlil^c
• 关键词：Manganites ; X-ray diffraction ; Magnetization ; Magnetocaloric effect
• 刊名：Ceramics International
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：43
• 期：1
• 页码：133-143
• 全文大小：2214 K

文摘

The effects of partial silver substitution on the structural, magnetic and magnetocaloric properties of Pr_0.5Sr_0.5-xAg_xMnO₃ (0.0≤x≤ 0.4) compounds have been studied. Our powder specimens are synthesized using the sol-gel method at high temperatures. X-Ray diffraction study reveals that all compounds crystallize in the distorted orthorhombic symmetry with Pbnm space group. Magnetization measurements versus temperature under 0.05 T reveal the presence of an antiferromagnetic (AFM) to ferromagnetic (FM) transition at low temperatures for the parent compound, followed by a second one from FM to paramagnetic state (PM). Ag doping is found to reinforce the FM behavior with a Curie temperature (T_C) increasing from 268 (x=0.0) to 305 K(x=0.2). However, for higher Ag amount, T_C decreases again from 285 K (x=0.3) to 170 K (x  =0.4). The maximum of the magnetic entropy change ($-\Delta S_M^{max}$) was calculated using the isothermal magnetization curves M (H) under magnetic field change of 5 T and is found to be 4.7 J/(kg K) for x=0.3. The relative cooling power (RCP) turns out to be 188 J/kg and 229 J/kg for x=0.0 and x=0.1, respectively. This suggests that these compounds may be suitable candidates for magnetic refrigeration.