Facile sonochemical synthesis of high-moment magnetite (Fe3O4) nanocube
Facile sonochemical synthesis of high-moment magnetite (Fe3O4) nanocube
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DOI：
10.1007/s11051-012-1354-y
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发表时间：
2013-01-01
影响因子：
2.5
通讯作者：
Kim, CheolGi
中科院分区：
文献类型：
--
作者：
Abbas, Mohamed;Takahashi, Migaku;Kim, CheolGi
以廉价无毒的金属盐（FeSO4中心点7H(2)O）为原料，采用单反应声化学方法在水介质中合成了粒径均匀、粒径约为80 nm的单分散磁铁矿纳米立方。经过600℃退火处理，磁铁矿纳米立方体的结晶度得到提高，形状和尺寸分布均匀，在700℃退火温度下，磁铁矿纳米立方体的形状发生畸变，尺寸分布较宽。纳米粒子的磁性表征表明，合成样品在5 K时的饱和磁化强度为91 emu/g，在600℃真空室中退火后的饱和磁化强度为94.8 emu/g。然而，饱和磁化强度随着退火温度的进一步升高而降低，这是由于形状各向异性畸变和交换键断裂引起的表面薄磁死层的存在，以及颗粒表面的自旋倾斜以及少量磁赤铁矿相的形成。
Monodisperse magnetite nanocubes with uniform particle size of about 80 nm have been synthesized in aqueous medium by single reaction sonochemical method using inexpensive and nontoxic metal salt (FeSO4 center dot 7H(2)O) as reactant. The crystallinity of the magnetite nanocube is enhanced by annealing treatment up to 600 degrees C with uniform shape and size distribution, after that a distortion in shape and a broad size distribution are obtained at 700 degrees C annealing temperature. The magnetic characterization of the nanoparticles reveals saturation magnetization of 91 emu/g at 5 K for as-synthesized sample and 94.8 emu/g for the sample which annealed at the temperature of 600 degrees C in a vacuum chamber. However, the saturation magnetization has been observed to decrease with further increase in annealing temperature and this has been attributed to the presence of a thin magnetic dead layer at the surface caused by shape anisotropy distortion and broken exchange bonds, and spin canting on the surface of the particles in addition to the formation of a small amount of maghemite phase.