Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States.
J Am Chem Soc. 2010 Nov 17;132(45):15997-6005. doi: 10.1021/ja104314c. Epub 2010 Oct 21.
EuS nanocrystals (NCs) were doped with Gd resulting in an enhancement of their magnetic properties. New EuS and GdS single source precursors (SSPs) were synthesized, characterized, and employed to synthesize Eu(1-x)Gd(x)S NCs by decomposition in oleylamine and trioctylphosphine at 290 °C. The doped NCs were characterized using X-ray diffraction, transmission electron microscopy, and scanning transmission electron microscopy, which support the uniform distribution of Gd dopants through electron energy loss spectroscopy (EELS) mapping. X-ray absorption spectroscopy (XAS) revealed the dopant ions in Eu(1-x)Gd(x)S NCs to be predominantly Gd(3+). NCs with a variety of doping ratios of Gd (0 ≤ x < 1) were systematically studied using vibrating sample magnetometry and the observed magnetic properties were correlated with the Gd doping levels (x) as quantified with ICP-AES. Enhancement of the Curie temperature (T(C)) was observed for samples with low Gd concentrations (x ≤ 10%) with a maximum T(C) of 29.4 K observed for NCs containing 5.3% Gd. Overall, the observed T(C), Weiss temperature (θ), and hysteretic behavior correspond directly to the doping level in Eu(1-x)Gd(x)S NCs and the trends qualitatively follow those previously reported for bulk and thin film samples.
EuS 纳米晶体 (NCs) 被 Gd 掺杂，从而增强了其磁性。合成了新型 EuS 和 GdS 单源前体 (SSP)，并对其进行了表征，然后在 290°C 下通过在油胺和三辛基膦中的分解来合成 Eu(1-x)Gd(x)S NCs。掺杂 NCs 的特性使用 X 射线衍射、透射电子显微镜和扫描透射电子显微镜进行了表征，电子能量损失光谱 (EELS) 映射支持 Gd 掺杂剂的均匀分布。X 射线吸收光谱 (XAS) 表明 Eu(1-x)Gd(x)S NCs 中的掺杂离子主要为 Gd(3+)。通过振动样品磁强计对具有各种 Gd 掺杂比 (0 ≤ x < 1) 的 NCs 进行了系统研究，并通过电感耦合等离子体原子发射光谱法 (ICP-AES) 定量分析了观察到的磁性与 Gd 掺杂水平 (x) 之间的相关性。对于低 Gd 浓度 (x ≤ 10%) 的样品，观察到居里温度 (T(C)) 的增强，对于含有 5.3% Gd 的 NCs，观察到最大 T(C) 为 29.4 K。总体而言，观察到的 T(C)、Weiss 温度 (θ) 和磁滞行为与 Eu(1-x)Gd(x)S NCs 的掺杂水平直接相关，并且趋势定性上与体相和薄膜样品的先前报道一致。
