磁性纳米粒子的合成、功能化及应用

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Co-Precipitation
NaOH FeCl2 (1 mol) + FeCl3 (2 mol)
oxidation Fe3O4
γ-Fe2O3
Ferromagnet
Superparamagnet
• Surface Effects
As the particle size decreases, a large percentage of all the atoms in a nanoparticle are surface atoms, which implies that the surface spins make an important contribution to the magnetization.
Magnetic NPs
Finite-size Effects Surface Effects
Control monodispersed NPs size
Surface coatings
Synthesis of Magnetic NPs
• Co-Precipitation of different metallic salts • Thermal Decomposition of Organometallic precursors • Polyol Reduction • Microemulsion • Hydrothermal Synthesis
instance.
http://www.kva.se/KVA_Root/eng/_news
Outline
Special Features
Magnetic Nanoparticles
Synthesis
Protection or Functionalization
Applications
What will happen on the nanoscale
1nm 0.1nm
Fe nanomaterials High coercivity superparamagnet
Special Features
• Finite-Size Effects
Materials properties are very different from bulk materials when the size of particles ranges from 1 to 100nm, such as single-domain limit and superparamagnetic limit
米
毫米
微米
奈米 埃
(m)
(mm) 100m 10m 1m 100nm 10nm nm 0.1nm
人高
細沙
微生物 細胞 血球 細菌
頭髮 50~100
m
病毒 高分子 糖分子 氫原子 DNA
1cm 1μm
Fe Bulk Materials Silvery white ferromagnet
100nm
10nm
磁性纳米粒子的合成、功能化 及应用
Magnet
Sinan of the Warring States Period
Nanomagnet in the biology
Fra Baidu bibliotek
Nobel Prize in Physics 2007
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Dr. Stuart S.P. Parkin is an exp(GeriiamntenMtaalgpnheytosriceissitstaatnIcBeM) ’s Almaden Research Center in San Jose, California. His discionv1e9ri8e8s into the behavior of thin-film
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magnetic structures were critical in enabling recent increases in the data density
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