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首页> 外文期刊>The journal of physical chemistry, C. Nanomaterials and interfaces >Defect Structure Guided Room Temperature Ferromagnetism of Y-Doped CeO2 Nanoparticles
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Defect Structure Guided Room Temperature Ferromagnetism of Y-Doped CeO2 Nanoparticles

机译：Y掺杂CeO2纳米粒子的缺陷结构指导的室温铁磁性

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摘要

In this study, the defect structure of Y doped CeO2 nanoparticles (NPs) was investigated systematically by using spectroscopy and microscopy. The doping level of Y ranges from 0% to 15%. It is demonstrated that Y~(3+) substitutes Ce and governs the formation of oxygen vacancy. At low doping level, Y~(3+) randomly distributed throughout the particle. However, as doping level increased above 9%, Y~(3+) aggregates at the surface and forms Y-rich clusters. Room temperature ferromagnetism (FM) was observed in these Y-doped CeO2 NPs. It is found that the value of saturation magnetization (Ms) increases until Y reaches 9%, then it decreases. Raman, X- ray absorption near edge spectroscopy and X-ray magnetic circular dichroism (XMCD) analysis has provided several aspects on the electronic properties of theses nanoparticles. A charge delocalization occurs upon Y doping on the Ce(Y)-O(V_0)-Ce(Y) orbitals. The magnetism is evidenced by XMCD spectroscopy only on Ce orbitals, and the magnetism intensity is mainly related to the amount of Ce~(3+) at the surface. These features plead for the presence of a defect band at the surface, related to the Ce~(3+)—Y interaction, as the origin of the ferromagnetism.
机译：在这项研究中，通过使用光谱学和显微镜系统地研究了掺Y的CeO2纳米颗粒（NPs）的缺陷结构。 Y的掺杂水平在0％至15％的范围内。结果表明，Y〜（3+）取代了Ce并控制了氧空位的形成。在低掺杂水平下，Y〜（3+）随机分布在整个粒子中。然而，当掺​​杂水平增加到9％以上时，Y〜（3+）在表面聚集并形成富Y团簇。在这些掺Y的CeO2纳米粒子中观察到室温铁磁（FM）。发现饱和磁化强度（Ms）的值一直增大，直到Y达到9％，然后才减小。拉曼光谱，近边缘光谱法的X射线吸收和X射线磁性圆二色性（XMCD）分析提供了这些纳米粒子的电子特性的几个方面。在Ce（Y）-O（V_0）-Ce（Y）轨道上进行Y掺杂时会发生电荷离域。 XMCD光谱法仅在Ce轨道上证明了磁性，并且磁性强度主要与表面的Ce〜（3+）量有关。这些特征表明在表面存在与Ce〜（3 +）-Y相互作用有关的缺陷带，这是铁磁性的起源。

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