Magnetic properties of Mg-ferrite nanoparticles
Magnetic properties of Mg-ferrite nanoparticles
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DOI：
10.1016/j.jmmm.2006.10.737
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发表时间：
2007-03-01
影响因子：
2.7
通讯作者：
Uehashi, T.
中科院分区：
文献类型：
--
作者：
Ichiyanagi, Y.;Kubota, M.;Uehashi, T.
采用湿化学法制备了无定形SiO2包裹的MgFe2O4纳米颗粒，并对其磁性能进行了研究。根据X射线衍射图估计这些粒子的直径在3到8纳米之间。在+/- 50 kO磁场下对每个样品进行磁化测量。根据场冷（FC）和零场冷（ZFC）磁化的温度依赖性，确定了阻滞温度T-b在30K左右。M - H曲线表明在阻滞温度Tb以下存在磁滞现象。在5K时发现了一个大的约1000欧的矫顽力。用电炉在空气中对制备的样品进行热处理。在淬火样品和退火样品之间发现了明显的磁化差异。这一现象说明尖晶石结构中的Mg2+离子会随机分布在A位和B位。(c) 2006 Elsevier b.v.保留所有权利。
MgFe2O4 nanoparticles encapsulated in amorphous SiO2 were prepared by means of a wet chemical method, and the magnetic properties were studied. The diameters of these particles were estimated from X- ray diffraction patterns as ranging from 3 to 8 nm. Magnetization measurements were carried out for each sample under a +/- 50 kO field. The blocking temperature, T-b, was determined to be around 30K from the temperature dependence of both the field- cooled ( FC) and the zero-field- cooled ( ZFC) magnetization. The M - H curve indicated the presence of ferromagnetic behavior with hysteresis below the blocking temperature, Tb. A large coercive force of about 1000 Oe was found at 5K. Heat treatment was carried out for the prepared samples using an electric furnace in air. A clear difference in magnetization was found between the quenched samples and annealed samples. This phenomenon suggests that the Mg2+ ions in the spinel structure would be randomly distributed into both the A- and the B- site. (c) 2006 Elsevier B. V. All rights reserved.