Structural and magnetic properties of uniform magnetite nanoparticles prepared by high temperature decomposition of organic precursors
Structural and magnetic properties of uniform magnetite nanoparticles prepared by high temperature decomposition of organic precursors
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DOI：
10.1088/0957-4484/17/11/010
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发表时间：
2006-06-14
期刊：
影响因子：
3.5
通讯作者：
Serna, C. J.
中科院分区：
文献类型：
--
作者：
Roca, A. G.;Morales, M. P.;Serna, C. J.
在表面活性剂存在下，通过在有机介质中热分解铁前体，获得了三种不同尺寸的低于单畴磁行为极限的磁铁矿纳米颗粒（Fe3O4）。通过TEM获得的平均粒径，从X射线衍射计算的晶体尺寸和从在室温下测量的磁化曲线计算的磁直径之间的良好的一致性表明，样品由均匀的，结晶的和孤立的磁铁矿纳米颗粒的尺寸在5和11 nm之间。高饱和磁化强度和高初始磁化率值已被发现，后者随着颗粒尺寸的减小而减小。对各向异性的主要贡献是磁晶和形状各向异性，因为表面各向异性被共价键合到纳米颗粒表面的油酸分子抑制。
Magnetite nanoparticles (Fe3O4) of three different sizes below the limit for single domain magnetic behaviour have been obtained by thermal decomposition of an iron precursor in an organic medium in the presence of a surfactant. Good agreement between mean particle size obtained by TEM, crystal size calculated from x-ray diffraction and magnetic diameter calculated from magnetization curves measured at room temperature shows that the samples consist of uniform, crystalline and isolated magnetite nanoparticles with sizes between 5 and 11 nm. High saturation magnetization and high initial susceptibility values have been found, the latter decreasing as the particle size decreases. The main contribution to the anisotropy is magnetocrystalline and shape anisotropy, since surface anisotropy is suppressed by the oleic acid molecules which are covalently bonded to the nanoparticle surface.