Synthesis and magnetic properties of magnetite-silicate nanocomposites derived from iron oxide of bacterial origin.
Synthesis and magnetic properties of magnetite-silicate nanocomposites derived from iron oxide of bacterial origin.
复制标题
细菌来源的氧化铁衍生的磁铁矿-硅酸盐纳米复合材料的合成和磁性。
DOI：
10.1016/j.matchemphys.2012.08.070
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发表时间：
2012
影响因子：
4.6
通讯作者：
H
中科院分区：
文献类型：
--
作者：
Hashimoto;H
以水栖铁氧化细菌赭纤发菌（Leptothrix ochracea）产生的氧化铁微管为原料，制备了含有Fe 3 O 4纳米颗粒的磁性纳米复合材料。微管主要由含Si的氢氧化铁组成，其显示出与2-线水铁矿相似的宽X射线衍射图案。在高于325°C的还原性气氛中进行适度热处理后，铁离子被部分还原为亚铁态，在非晶硅酸盐基体中形成具有尖晶石型结构的纳米晶Fe 3 O 4。Fe 3 O 4纳米颗粒的平均晶粒尺寸估计为几个纳米的顺序。在500°C热处理的样品在室温下表现出相当大的磁化强度和超顺磁性行为，并且在低温下发生超自旋-玻璃相互作用。在530°C以上的进一步热处理中，Fe 3 O 4被还原为方铁矿（Fe 1 −xO），并最终结晶为铁金属（α-Fe）和硅酸亚铁（Fe 2SiO 4）。
Magnetic nanocomposites containing magnetite (Fe3O4) nanoparticles were prepared from iron oxide microtubules produced by Leptothrix ochracea, a species of water-habitant iron-oxidizing bacteria. The microtubules were mainly composed of Si-containing ferric hydroxide that shows a broad X-ray diffraction pattern similar to that of 2-line ferrihydrite. After moderate heat treatment in a reductive atmosphere above 325°C, the ferric ions were partially reduced to a ferrous state, and nanocrystalline Fe3O4with a spinel-type structure was formed in a noncrystalline silicate matrix. The average crystallite size of the Fe3O4nanoparticles was estimated to be in the order of a few nanometers. The sample heat-treated at 500°C exhibited considerable magnetization together with superparamagnetic behavior at room temperature, and super-spin-glass interaction occurred at low temperature. On further heat treatment above 530°C, Fe3O4was reduced to wüstite (Fe1−xO) and finally crystallized into iron metal (α-Fe) and ferrous silicate (Fe2SiO4).