New technique for synthesizing iron ferrite magnetic nanosized particles
New technique for synthesizing iron ferrite magnetic nanosized particles
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DOI：
10.1021/la960854q
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发表时间：
1997-07-23
期刊：
影响因子：
3.9
通讯作者：
Pileni, MP
中科院分区：
文献类型：
--
作者：
Feltin, N;Pileni, MP
十二烷基硫酸亚铁，Fe(DS)(2)，胶束溶液用于制备纳米级磁性颗粒，其尺寸由表面活性剂浓度和温度控制。平均粒径范围为3.7至11.6 nm，标准偏差范围为0.22至0.34。与在均匀溶液中获得的相比，当在非常低的反应物浓度和室温下进行合成时可以获得铁氧体颗粒。此外，当使用 Fe(II) 作为反应物进行合成时，可以获得纳米颗粒，而在均匀溶液中则形成微米范围内的颗粒。颗粒结晶度随合成温度的变化而变化，从 25 摄氏度时的相当低的值到 50 摄氏度及以上时的相当高的值。这些粒子具有超顺磁性行为的特征。饱和磁化强度随着颗粒尺寸的增加而减小，这可以用界面处的非共线结构来解释。低结晶度颗粒的特征是磁直径小于透射电子显微镜测定的磁直径。这归因于晶体的各向异性。
Ferrous dodecyl sulfate, Fe(DS)(2), micellar solution was used to make nanosized magnetic particles whose size is controlled by the surfactant concentration and by temperature. The average particle size varies from 3.7 to 11.6 nm, with a standard deviation ranging from 0.22 to 0.34. In contrast to what is obtained in homogeneous solution, iron ferrite particles can be obtained when the synthesis is performed at very low reactant concentrations and room temperature. Furthermore, nanoparticles are obtained when the syntheses are performed using Fe(II) as reactant whereas in homogeneous solution particles in the micrometric range are formed. The particle crystallinity varies with the synthesis temperature, going from fairly low values at 25 degrees C to fairly high values at 50 degrees C and above. The particles are characterized by superparamagnetic behavior. The saturation magnetization decreases with particle size, which is explained in terms of non-collinear structure at the interface. Particles with low crystallinity are characterized by magnetic diameters smaller than those determined by transmission electron microscopy. This is attributed to crystalline anisotropy.