Electron magnetic resonance study of monovalent Na doping in Pr_0.6Sr_{0.4鈭?span style='font-style: italic'>x}Na_xMnO₃ manganites

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• 作者：Rachid Thaljaoui^a ; ^b ; ^c ; Wahiba Boujelben^a ; ^{Wahibaboujelben@yahoo.fr} ; Marek Pę ; kał ; a^c ; Jadwiga Szydł ; owska^c ; Abdelwaheb Cheikhrouhou^a ; ^d
• 关键词：Manganites ; Ferromagnetic and electron paramagnetic resonance ; Polaron hopping ; Magnetic interactions
• 刊名：Journal of Alloys and Compounds
• 出版年：2012
• 期刊代码：45_09258388
• 类别：ms
• 出版时间：15 June, 2012
• 卷：526
• 期：Complete
• 页码：98-102
• 文件大小：837 K

摘要

Effect of monovalent Na doping on the magnetic properties is studied in Pr_0.6Sr_0.4鈭?em>xNa_xMnO₃ system (x = 0, 0.05) using X-band electron magnetic resonance and magnetization measurements. Temperature variation of magnetic resonance spectra of doped and undoped manganites is analyzed for paramagnetic and ferromagnetic states and compared to similar systems. In paramagnetic phase the magnetic susceptibility proportional to resonance signal intensity is found to obey the Curie-Weiss law. The effective magnetic moment becomes smaller in doped manganite. The paramagnetic Curie temperature derived from signal intensity equals to 312 and 306 K for the undoped and doped manganites, respectively, and is close to values obtained from magnetization variation in paramagnetic phase. The activation energy determined using the adiabatic small polaron hopping model is higher for the undoped than the doped manganite, which proves that the Na doping slightly reduces the Mn³⁺/Mn⁴⁺ double exchange interactions.