Tailoring magnetic properties of spinel nanoparticles by silica coating: Importance of surfaces and interfaces

通过二氧化硅涂层定制尖晶石纳米颗粒的磁性：表面和界面的重要性

• 批准号: 156604961
• 负责人: Professor Dr. Heiko Wende
• 金额: --
• 依托单位: Fakultät für Physik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2009
• 资助国家: 德国
• 起止时间: 2008-12-31 至 2013-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/156604961?language=en
• 关键词: Tailoring; magnetic; properties; spinel; nanoparticles

Spinel nanoparticles have attracted increasing attention because of their potential applications in magnetic recording media, ferrofluids, and biomedical technology. By colloidal synthetic approaches for monodisperse magnetic spinel ferrite and silicacoated ferrite nanocrystals we tune the size of the ferrite core and the silica shell by varying the reaction parameters in the microemulsion system. This will allow us to study the effect of the core’s size and shell’s thickness on the magnetic properties as, e.g., the effective anisotropy and the superparamagnetic blocking temperature in a systematic way. A detailed magnetic characterisation of the particles will be performed by Mössbauer and x-ray absorption spectroscopy. Both techniques give the possibility to distinguish the magnetic atoms with different valencies (like, e.g., Fe3+ and Fe2+ in the inverse spinel Fe3O4) on different lattice sites. In addition, by x-ray absorption spectroscopy and its associated circular dichroism the spin and orbital moment will be separated which is crucial for the microscopic understanding of the important magnetic properties including magnetic anisotropy.

尖晶石纳米颗粒因其在磁记录介质、铁磁流体和生物医学技术方面的潜在应用而受到越来越多的关注。通过胶体法合成单分散磁性尖晶石铁氧体和硅涂层铁氧体纳米晶，通过改变微乳液体系中的反应参数来调整铁氧体核和二氧化硅壳的尺寸。这将使我们能够系统地研究磁芯尺寸和壳层厚度对磁性质的影响，如有效各向异性和超顺磁阻塞温度。粒子的详细磁性特征将通过Mössbauer和x射线吸收光谱进行。这两种技术都提供了在不同晶格位置上区分具有不同价态的磁性原子的可能性（例如，逆尖晶石Fe3O4中的Fe3+和Fe2+）。此外，通过x射线吸收光谱及其相关的圆二色性将分离自旋力矩和轨道力矩，这对于微观理解包括磁各向异性在内的重要磁性质至关重要。

项目成果

Effect of silica capping on the oxidation of Fe 3 O 4 nanoparticles in dispersion revealed by x-ray absorption spectroscopy

• DOI: 10.1103/physrevb.85.235113
• 发表时间: 2012-06
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: A. Warland;C. Antoniak;M. Darbandi;C. Weis;J. Landers;W. Keune;H. Wende

Blocked-micropores, surface functionalized, bio-compatible and silica-coated iron oxide nanocomposites as advanced MRI contrast agent

堵塞微孔、表面功能化、生物相容性和二氧化硅涂层氧化铁纳米复合材料作为先进 MRI 造影剂

• DOI: 10.1007/s11051-013-1664-8
• 发表时间: 2013
• 期刊: Journal of Nanoparticle Research
• 影响因子: 2.5
• 作者: M. Darbandi;S. Laurent;M. Busch;Z. - A. Li;Y. Yuan;M. Krüger;M. Farle;M. Winterer;L. Vander Elst;R. N. Muller;H. Wende
• 通讯作者: H. Wende

Nanoscale size effect on surface spin canting in iron oxide nanoparticles synthesized by the microemulsion method

• DOI: 10.1088/0022-3727/45/19/195001
• 发表时间: 2012-05-16
• 期刊: JOURNAL OF PHYSICS D-APPLIED PHYSICS
• 影响因子: 3.4
• 作者: Darbandi, Masih;Stromberg, Frank;Wende, Heiko
• 通讯作者: Wende, Heiko