| 摘要 | Cobalt ferrite nano-particles were prepared using the co-precipitation method followed by annealing treatment. The formation of nano-particles with different composition, microstructure and sizes were confirmed by X-ray diffraction, Raman, thermogravimetric-differential thermal analysis and transmission electron microscope. The magnetic hysteresis loops measured at room temperature revealed smaller effective magnetic anisotropy constant, coercivity and remanence ratio for the samples prepared by adding the NaOH solutions into the mixed solutions of Co(2+) and Fe(3+) ions due to the formation of Co(3+) ions. A small saturation magnetization and an enhanced coercivity were observed for the nano-particles prepared by adding the mixed solutions of Co(2+) and Fe(3+) ions into the NaOH solutions, which was related to the formation of outer layers with poor crystallization on the surfaces of the cobalt ferrite nano-crystals. Furthermore, the existence of these outer layers induced the oxidation of Co(2+) ions in cobalt ferrite nano-crystals at 200 and 300 degrees C, and led to a large change on the composition and magnetic properties. (C) 2010 Elsevier B.V. All rights reserved. |
| 部门归属 | [zhang, yue; yang, zhi; yin, di; liu, yong; fei, chunlong; xiong, rui; shi, jing; yan, gaolin] wuhan univ, dept phys, wuhan 430072, peoples r china. [zhang, yue; yang, zhi; yin, di; liu, yong; fei, chunlong; xiong, rui; shi, jing; yan, gaolin] wuhan univ, key lab acoust & photon mat & devices, minist educ, wuhan 430072, peoples r china. [zhang, yue; xiong, rui] hubei key lab organ & polymer optoelect mat, wuhan 430072, peoples r china. [shi, jing] acad sinica, int ctr mat phys, shenyang 110015, peoples r china.;xiong, r (reprint author), wuhan univ, dept phys, wuhan 430072, peoples r china;xiongrui1967@163.com
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| APA |
Y. Zhang.,Z. Yang.,D. Yin.,Y. Liu.,C. L. Fei.,...&G. L. Yan.(2010).Composition and magnetic properties of cobalt ferrite nano-particles prepared by the co-precipitation method.Journal of Magnetism and Magnetic Materials,322(21),3470-3475.
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