The present study reports the successful synthesis of Sn_1–xCr_xO₂ nanoparticles with doping content (x) ranging from 0 to 0.20. Samples were synthesized by a polymer precursor method using SnCl₂·H₂O and Cr(NO₃)₃·5H₂O as metal ion suppliers. In all samples X-ray diffraction data show one single-phase formation (rutile-type), with crystalline size (crystal strain) decreasing (increasing) monotonically while increasing the x content, which are assigned to substitutional solution of Cr and Sn ions in the crystalline structure. In addition to a weak magnetic ordering observed in a few samples (x = 0.01, 0.02, 0.03, and 0.05), paramagnetism is the main magnetic contribution in all synthesized samples, which is due to the presence of two chromium ions (Cr³⁺ and Cr⁴⁺). X-ray photoelectron spectroscopy measurements confirm the coexistence of Cr³⁺ and Cr⁴⁺ ions in excellent agreement with the monotonic decrease of the [Cr³⁺]/[Cr⁴⁺] versus doping content (x), assessed from the fitting of the susceptibility versus temperature data using the Curie–Weiss law.

中文翻译：

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Cr掺杂的SnO ₂纳米颗粒中Cr ³⁺和Cr ⁴⁺共存的证据：结构和磁性研究

本研究报告成功合成了Sn含量为（x）为0至0.20的Sn _{1- x} Cr _x O ₂纳米颗粒。使用SnCl ₂ ·H ₂ O和Cr（NO ₃）₃ ·5H ₂ O作为金属离子供应商，通过聚合物前驱体方法合成了样品。在所有样品中，X射线衍射数据均显示出一种单相形成（金红石型），晶体尺寸（晶体应变）单调减小（增大），而增大x含量，它们分配给晶体结构中Cr和Sn离子的替代溶液。除了在一些样品中观察到的弱磁性排序（x = 0.01、0.02、0.03和0.05）外，顺磁性是所有合成样品中的主要磁性成分，这是由于存在两个铬离子（Cr ³⁺和Cr ⁴⁺）。X射线光电子能谱测量证实Cr ³⁺和Cr ⁴⁺离子共存，与[Cr ³⁺ ] / [Cr ⁴⁺ ]与掺杂含量（x）的单调降低相比，具有极好的一致性，这是根据X射线的拟合确定的。使用居里-魏斯定律的磁化率与温度数据。