【作者】 韩芍娜；

【导师】 李建；

【作者基本信息】 西南大学 ， 凝聚态物理， 2009， 硕士

【摘要】 本文用共沉淀法制备出CoFe₂O₄微粒、p-NiFe₂O₄微粒以及Ni₂O₃/Fe₂O₃复合型微粒,用X射线衍射仪（XRD）、X射线能量色散光谱仪（EDX）、X射线光电子能谱（XPS）、透射电子显微镜（TEM）分别对上述三种纳米微粒的晶体结构、元素比例、内部结构以及表面形态进行表征。用Massart法制备出相应的体积分数为2%的单元磁性液体作为母液待用。CoFe₂O₄磁性液体和p-NiFe₂O₄磁性液体二者等体积进行混合,作为二元磁性液体的母液,而后进行稀释,以制取不同体积分数的磁性液体,分别对其进行密度、粘度、磁性、磁光的测量。比较单一的CoFe₂O₄磁性液体与二元磁性液体中的CoFe₂O₄部分的磁性,分析弱磁性p-NiFe₂O₄微粒在二元磁性液体中的调制作用。在二元的CoFe₂O₄-p-NiFe₂O₄磁性液体中,CoFe₂O₄微粒是场致结构的主体,p-NiFe₂O₄微粒可能抑制或者增强场致结构的形成。在磁性测量结果中发现p-NiFe₂O₄微粒的调制作用不是单调的线性关系,而是存在一个极限临界体积分数,当加入的弱磁性液体的体积分数在这一临界体积分数之下时,随着弱磁性微粒的增加,二元磁性液体中的强磁性部分将随之增强,反之,当加入的弱磁性液体的体积分数大于这一临界体积分数之时,随着弱磁性微粒的增加,二元磁性液体中的强磁性部分会随之减小。结果表明,二元体系中的磁化性质不等于单元体系磁化性质的线性叠加。测量了稳定磁场作用下透过单元、二元磁性液体的光透射变化情况,从微观上进行了分析,根据微粒链的形成与运动模型,对二元磁性的光透射率变化进行了解释,研究了二元磁性液体中弱磁性微粒对强磁性的调制作用。对于Ni₂O₃/Fe₂O₃纳米微粒及磁性液体进行初步研究。更多还原

【Abstract】 In this paper, CoFe₂CO₄ nanoparticles, p-NiFe₂O₄ nanoparticles and Ni₂O₃/Fe₂O₃ nanoparticles are prepared by chemical co-precipitation. Using the XRD, EDX, XPS, TEM analyze the nanoparticles’ crystal structure, atomic ratios, Internal structure and morphology, respectively.These two nanoparticles are used to product 2 percent mother fluids by Massart method, respectively, then the two fluids are mixed with the same volume to obtain the binary ionic fluids. Then dilute mother fluids, we can obtain different ferrofluids of volume fraction, measure the density, viscosity, magnetization, magnetic optic.Compared the magnetic of single CoFe₂O₄ and the CoFe₂O₄ which in the binary ferrofluids, analyzing the weak magnetic p-NiFe₂O₄ nanoparticles’ modulation which in the binary ferrofluids. In binary CoFe₂O₄-p-NiFe₂O₄ ferrofluids, CoFe₂O₄ nanoparticles are theme of field-induced, p-NiFe₂O₄ nanoparticles may suppress or enhance the field-induced composition. In magnetic measuring, It found that the modulation of the p-NiFe₂O₄ nanoparticles is not monotone linear relationship, but to be a critical volume fraction, when weak magnetic ferrofluids under this critical volume fraction, the magnetic part of binary ferrofluids will enhance with the weak magnetic nanoparticles added, or when weak magnetic ferrofluids over this critical volume fraction, the the magnetic part of binary ferrofluids will decrease with the weak magnetic nanoparticles added. It can conclude that the magnetization of the binary system is not a simply summed.The transmitted ration of light through single and binary ferrofluids under stable magnetic field are measured, according to the model of particles chains’ formed and moved, it can explain the transmitted changeable of binary ferrofluids, studying the modulation effect of weak magnetic nanoparticles.Ni₂O₃/Fe₂O₃ nanoparticles and ferrofluids are preliminary researched.更多还原