Co-doped CeO₂ fabricated using the conventional solid-state reaction method demonstrates ferromagnetism at room temperature (RT). To investigate the origin of ferromagnetism at RT, powder X-ray diffraction analysis is first performed, in which pattern changes due to Co doping are not indicated. Subsequently, local environment analysis is carried out using X-ray absorption near-edge structure (XANES) measurements at the Co K-edge, demonstrating the metallic valence state of Co. Hence, it is confirmed that Co exists as nanosized small particles in CeO₂, which demonstrates ferromagnetism at RT.

中文翻译：

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Co掺杂CeO ₂中室温铁磁性的起源

使用常规固态反应方法制造的共掺杂 CeO ₂在室温 (RT) 下表现出铁磁性。为了研究 RT 铁磁性的起源，首先进行粉末 X 射线衍射分析，其中没有指出由于 Co 掺杂引起的图案变化。随后，在 Co K 边缘使用 X 射线吸收近边缘结构 (XANES) 测量进行局部环境分析，证明了 Co 的金属价态。 因此，证实 Co 以纳米级小颗粒形式存在于 CeO_{图 2}显示了 RT 下的铁磁性。