期刊
JOURNAL OF NANOPARTICLE RESEARCH
卷 15, 期 4, 页码 -出版社
SPRINGER
DOI: 10.1007/s11051-013-1514-8
关键词
Magnetic nanoparticles; Superparamagnetism; X-ray absorption spectroscopy; Antiphase boundaries
资金
- European project MAGNIFYCO [NMP4-SL-2009-228622]
- Spanish Ministerio de Economia y Competitividad [CSD2009-00013, MAT2011-27470-C02-02, FIS-2008-06249]
- Madrid Region Council project NANOBIO MAGNET [S2009/MAT-1726]
- Spanish MICINN [CTQ2009-06959, RYC-2010-05821]
In this work we investigate the magnetic properties of iron oxide nanoparticles obtained by two-step synthesis (seeded-growth route) with sizes that range from 6 to 18 nm. The initial seeds result monocrystalline and exhibit ferromagnetic behavior with low saturation field. The subsequent growth of a shell enhances the anisotropy inducing magnetic frustration, and, consequently, reducing its magnetization. This increase in anisotropy occurs suddenly at a certain size (similar to 10 nm). Electronic and structural analysis with X-ray absorption spectroscopy indicates a step reduction in the oxidation state as the particle reaches 10 nm size while keeping its overall structure in spite of the magnetic polydispersity. The formation of antiphase magnetic boundaries due to island percolation in the growing shells is hypothesized to be the mechanism responsible of the magnetic behavior, as a direct consequence of the two-step synthesis route of the nanoparticles.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据