Mosivand Saba, Monzon Lorena M A, Kazeminezhad Iraj, Coey J Michael D
Physics Department, Trinity College, Dublin 2, Ireland.
Int J Mol Sci. 2013 May 17;14(5):10383-96. doi: 10.3390/ijms140510383.
Magnetite nanoparticles were synthesized by electrocrystallization in the presence of thiourea or sodium butanoate as an organic stabilizer. The synthesis was performed in a thermostatic electrochemical cell containing two iron electrodes with an aqueous solution of sodium sulfate as electrolyte. The effects of organic concentration, applied potential and growth temperature on particle size, morphology, structure and magnetic properties were investigated. The magnetite nanoparticles were characterized by X-ray diffraction, electron microscopy, magnetometry and Mössbauer spectrometry. When the synthesis is performed in the presence of sodium butanoate at 60 °C, a paramagnetic ferric salt is obtained as a second phase; it is possible to avoid formation of this phase, increase the specific magnetization and improve the structure of the oxide particles by tuning the growth conditions. Room-temperature magnetization values range from 45 to 90 Am2kg-1, depending on the particle size, type of surfactant and synthesis conditions. Mössbauer spectra, which were recorded at 290 K for all the samples, are typical of nonstoichiometric Fe3-δO4, with a small excess of Fe3+, 0.05 ≤ δ ≤ 0.15.
在硫脲或丁酸钠作为有机稳定剂存在的情况下，通过电结晶法合成了磁铁矿纳米颗粒。合成过程在一个恒温电化学池中进行，该池包含两个铁电极，以硫酸钠水溶液作为电解质。研究了有机浓度、施加电势和生长温度对颗粒尺寸、形态、结构和磁性的影响。通过X射线衍射、电子显微镜、磁强计和穆斯堡尔光谱对磁铁矿纳米颗粒进行了表征。当在60℃下于丁酸钠存在的情况下进行合成时，会得到一种顺磁性铁盐作为第二相；通过调整生长条件，可以避免该相的形成，提高比磁化强度并改善氧化物颗粒的结构。室温磁化值范围为45至90 Am2kg-1，这取决于颗粒尺寸、表面活性剂类型和合成条件。所有样品在290 K下记录的穆斯堡尔光谱是典型的非化学计量比Fe3-δO4，其中Fe3+略有过量，0.05≤δ≤0.15。
