Microscopic understanding of particle-matrix interaction in magnetic hybrid materials by elementspecific spectroscopy

通过元素特定光谱对磁性杂化材料中颗粒-基体相互作用的微观理解

• 批准号: 238114366
• 负责人: Professor Dr. Heiko Wende
• 金额: --
• 依托单位: Forschungsgruppe Experimentalphysik
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/238114366?language=en
• 关键词: Microscopic; understanding; particle; matrix; interaction

The understanding of the behavior of magnetic hybrid materials under working conditions is still imperfect. Especially on the local scale of the embedded nanoparticles the influence of external magnetic fields on Brownian movement, orientation and the coupling of the particles to the surrounding matrix material is not sufficiently understood. To investigate these properties of magnetic composite materials on the nanoscale in detail, the study of different (visco-) elastic media containing magnetic nanoparticles is planned in the scope of this project utilizing Mössbauer spectroscopy, AC-susceptometry and X-ray absorption spectroscopy at synchrotron facilities. Information on Néel relaxation as well as on Brownian particle motion can be obtained from the broadening and shape of the Mössbauer absorption lines. This provides new insights in the constrained particle mobility depending on the surrounding nanostructure of the individual matrix material and on possible variations of both relaxation processes at different external magnetic fields. Additionally, the orientation as well as the spin structure of the embedded particles can be determined from the intensity distribution of Mössbauer absorption lines. Findings from these experiments shall be substantiated by analyzing the element-specific electronic structure using X-ray absorption spectroscopy and X-ray circular dichroism, providing information on the magnetic properties of the particle-matrix interface. X-ray absorption spectra as well as Mössbauer spectra can be obtained in strong magnetic fields, yielding valuable information on the particle-matrix interaction under working conditions. A more detailed study of Brownian particle dynamics is planned by performing complementary measurements of the magnetic AC-susceptibility. The microscopic understanding achieved in this project will help to generate new functionalities of the hybrid materials by transferring this information to the groups synthesizing the systems.

对磁性混合材料在工作条件下的行为的理解仍然不完善。特别是在嵌入纳米颗粒的局部尺度上，外部磁场对布朗运动、方向以及颗粒与周围基质材料的耦合的影响尚未得到充分理解。为了在纳米尺度上详细研究磁性复合材料的这些特性，本项目计划在同步加速器设施中利用穆斯堡尔谱、交流电感受器和 X 射线吸收光谱来研究含有磁性纳米颗粒的不同（粘）弹性介质。关于尼尔弛豫以及布朗粒子运动的信息可以从穆斯堡尔吸收线的展宽和形状中获得。这为受限粒子迁移率提供了新的见解，该迁移率取决于单个基体材料的周围纳米结构以及不同外部磁场下两个弛豫过程的可能变化。此外，嵌入粒子的方向和自旋结构可以根据穆斯堡尔吸收线的强度分布来确定。这些实验的结果应通过使用 X 射线吸收光谱和 X 射线圆二色性分析元素特定的电子结构来证实，提供有关颗粒-基体界面的磁性的信息。在强磁场中可以获得 X 射线吸收光谱以及穆斯堡尔光谱，从而提供有关工作条件下颗粒-基体相互作用的有价值的信息。计划通过对交流磁化率进行补充测量来对布朗粒子动力学进行更详细的研究。该项目中实现的微观理解将有助于通过将这些信息传递给合成系统的小组来产生混合材料的新功能。