In this work, the local structure of ferrite nanoparticles (CoFe₂O₄) composed of a cobalt ferrite core surrounded by a thin layer of maghemite (CoFe₂O₄@γ-Fe₂O₃) was investigated by crossing analyses of X-ray powder Diffraction (XRD), X-ray Absorption Spectroscopy (XANES/EXAFS) and Diffraction Anomalous Fine Structure (DAFS). The proportion of the core and the shell phases was carefully checked by chemical analysis. The whole of these multiple complementary techniques confirmed the non-equilibrium site occupancy in the cobalt ferrite core. The cation distribution was precisely determined showing that about 15% of cobalt ions are located at tetrahedral sites. The results of EXAFS spectra indicated interatomic distances very close to bulk values. The mean coordination number of both metallic cations was found to be lower than expected for bare nanoparticles and reflected the core-shell structure in CoFe₂O₄@γ-Fe₂O₃ ones. Finally, DAFS analyses were applied to enlighten the local structure around iron atoms in specific Bragg planes.

在这项工作中，铁氧体纳米粒子的局部结构（由CoFe ₂ ö ₄钴铁氧体磁心组成）包围磁赤铁矿的薄层（由CoFe ₂ ö ₄ @了γ-Fe ₂ ö ₃通过对X射线粉末衍射（XRD），X射线吸收光谱（XANES / EXAFS）和衍射异常精细结构（DAFS）进行交叉分析研究。通过化学分析仔细检查核和壳相的比例。所有这些多种互补技术均证实了钴铁氧体磁芯中非平衡位点的占据。精确确定阳离子分布，表明约15％的钴离子位于四面体位置。EXAFS光谱的结果表明原子间距离非常接近整体值。两个金属阳离子的平均配位数被认为是低于预期裸纳米颗粒和反射CoFe中的核-壳结构₂ ö ₄ @了γ-Fe ₂ ö₃个 最后，DAFS分析用于启发特定布拉格平面中铁原子周围的局部结构。