【作者】 黄娟；

【导师】 谢文辉；

【作者基本信息】 华东师范大学 ， 纳米物理学， 2013， 硕士

【摘要】 Fel6N2化合物因具有高磁化强度、低矫顽力、较高的磁导率、耐磨耐腐蚀等优点,具有潜在的实用价值。本论文中,我们试图通过实验研究其制备技术,并通过第一原理电子结构计算方法从理论上研究过渡金属掺杂对其性质的影响。论文分为两个部分：实验部分和理论计算部分。1)实验：采用共沉淀法制备纳米Fe304粒子,进而通过NH3气氛进行氮化获取Fe-N化合物。我们研究了制备小颗粒Fe304纳米粒子前驱体的工艺,最终制备得到颗粒尺寸小于10nm的纳米Fe304粒子。然后将前驱体放在H2中还原后再通入NH3进行氮化。我们研究了不同氮化温度、氮化时间对生成物的影响。由于Fe16N2十分容易被氧化,且当前实验设备的限制,无法保存获取Fe16N2的最终产物,但这为以后制备打下了良好的基础。2)理论计算工作主要采用了基于全势线性缀加平面波方法进行第一原理电子结构计算研究。计算研究了Fe16N2的电子结构以及Fe-N间距、磁矩等物理性质。此外,我们着重研究了Mn、Co、Ni掺杂对Fe16N2性质的影响。计算得到Fe16N2的Fe原子的平均磁矩为2.43μB,FeⅢ原子的磁矩大于FeⅠ原子、FeⅡ原子。掺杂Mn、Co、Ni后,掺杂结构的Fe-N间距减小,总超精细场减小,FeⅠ原子、FeⅡ原子、FeⅢ原子的平均磁矩减小,掺杂结构的总磁矩减小。相对而言,Mn掺杂的结构较稳定,Co掺杂次之,Ni掺杂最差。更多还原

【Abstract】 Fe16N2compounds have potential practical value due to its high magnetization, low coercive force, high magnetic permeability, wear-resisting and high economic value, etc. In our work, we are trying to study the preparation technology through the experiment and research the changes when we doped transition metal into Fe16N2structure by using the first-principle calculation method.This article is mainly divided into two parts:experiment and theoretical calculation.1) In experimental section, firstly, we prepared Fe3O4nano-particles with co-precipitation method, and then nitrided in NH3atmosphere to abtain Fe-N compound. We studied the factors that may affect the size of Fe3O4and successfully prepared Fe3O4magnetic nano-particles which size is less than10nanometers. After that, the precursor was nitrided in NH3atmosphere after reduction in H2atmosphere for few hours. We have researched two important factors that may affect the final product:nitriding temperature and nitriding time. It is pity that our experiment fails in the end because Fe16N2can be easily oxidized in the air and our laboratory cannot afford the protect condition yet. But what I did laid a good foundation for the further experiment preparation.2) Theoretical calculation work mainly adopts the first-principle theory based on a full-potential Linearized Augmented Plane Wave method for the calculation of electronic structure. We studied some physical properties including the electronic structure, Fe-N distance and magnetic moment, etc. Otherwise, we research the influence when Mn, Co, Ni is doped into Fe16N2.Our calculation obtains that the average magnetic moment of Fe16N2is2.43μb, Felll atom’s magnetic moment is bigger than that of Fe I atom and Fe Ⅱ atom. After doping Mn, Co, Ni atom, the Fe-N distance and total hyperfine field become smaller. In doping structure, the average magnetic moment of three kinds of Fe atom is decrease, so is the total magnetic moment. Releatively speaking, Mn doping structure is the most stable case and Ni doping structure is the worst case.更多还原