Characterization of magnetic core–shell nanoparticles by fluxgate magnetorelaxometry, ac susceptibility, transmission electron microscopy and photon correlation spectroscopy—A comparativ
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- 作者：Frank Ludwig ; Erik Heim ; Meinhard Schilling
- 关键词：Magnetic nanoparticle ; Characterization ; Magnetorelaxometry ; Fluxgate magnetometer ; Ac susceptibility ; Photon correlation spectroscopy ; Transmission electron microscopy ; Magnetite
- 刊名：Journal of Magnetism and Magnetic Materials
- 出版年：2009
- 出版时间：May 2009
- 年：2009
- 卷：321
- 期：10
- 页码：1644-1647
- 全文大小：398 K
文摘
We have compared the structure parameters of magnetic core–shell nanoparticles determined from fluxgate magnetorelaxometry measurements applying the moment superposition model with the results from other methods. For the characterization of the magnetic cores, the nanoparticles are immobilized by freeze-drying. The core size distribution estimated for superparamagnetic Fe3O4 magnetic nanoparticles (MNPs) with polyacrylic acid shell agrees well with that from transmission electron microscopy measurements. The distribution of hydrodynamic diameters of nanoparticle suspensions estimated from magnetorelaxometry measurements is in good agreement with that obtained from ac susceptibility and photon correlation spectroscopy measurements. Advantages of magnetorelaxometry compared to the other two integral techniques are that it is fast and the signal is less dominated by larger particles.