铁氧体和氧化锌薄膜的溶液法制备、结构与性质

发布时间：2018-07-06 11:05

本文选题：尖晶石型铁氧体 + 氧化锌　；参考：《兰州大学》2010年博士论文

【摘要】： 随着现代通讯技术的迅猛发展,电子元器件的小型化、集成化、高频化必将使尖晶石型铁氧体薄膜大有用武之地。高密度垂直磁记录介质、薄膜磁头、薄膜变压器、薄膜电感器,多层膜器件以及生物工程、医疗诊断技术、磁性药物的发展将进一步加快铁氧体薄膜研究的步伐。尖晶石型铁氧体的结构和磁性质取决于掺杂离子的自身特性、浓度、占位以及制备方法。传统的铁氧体薄膜制备工艺中,材料的晶化需要在高温下进行(600℃),使得铁氧体薄膜不适合在耐热性较差的基底材料(如聚脂膜、聚合物颗粒、GaAs集成电路等)上沉积。目前低温合成尖晶石型铁氧体薄膜的主流方法是旋转喷涂法,但是这一方法存在制备过程复杂、浪费反应液等缺点,而且旋转喷涂法制务样品过程中溶液pH值较高,很容易优先生成氢氧化铁之类的沉淀物。Izaki发明的催化法可以克服上述困难,但是有关催化法的研究比较少,该方法目前仅能用来制备Fe304薄膜和成份单一的Fe0.16Zn2.84O4铁氧体薄膜,这对催化法的推广是不利的。本论文工作的第一个创新点是采用催化法制备出了NiZnCo掺杂的尖晶石型铁氧体薄膜并对其结构和性质进行了细致研究： (1)采用催化法,在80℃条件下,通过控制Fe(NO3)3、Zn(NO3)2、Ni(NO3)2、Co(NO3)2反应物的浓度,首次在硝酸盐和二甲基胺硼烷(DMAB)溶液中制备出了多组份掺杂的Ni0.11ZnxCo0.03Fe2.86-xO4(x=0.00、0.23、0.34、0.43和0.51)尖晶石型铁氧体薄膜。Zn2+离子易于沉积入薄膜中，，制备过程中控制Zn2+离子的浓度尤为关键。 (2)Ni0.11Zn0.51Co0.03Fe2.35O4薄膜是由40-50 nm的等轴颗粒组成。薄膜沉积1小时后,膜厚达到500 nm左右,表面较粗糙,从薄膜表面的最低谷到最高峰有200 nm的起伏。随着Zn2+离子含量的增加,组成薄膜的颗粒变得均匀细小。 (3)XRD谱分析表明,x从0增加到0.51,点阵常数从8.383 A增大到8.425A。由Scherrer公式计算出的晶粒尺寸在40 nm左右。随着Zn2+离子含量的增加,680 cm-1波数处的Raman峰发生了移动而且逐渐宽化,该峰可拟合为波数在655和687 cm-1的两个峰,他们分别归属于ZnO4和FeO4四面体的伸缩振动,证明Zn2+离子倾向于占据A位。 (4)薄膜的磁性可以通过调节Zn2+离子含量来控制。x增加,饱和磁化强度先增大后减小,在x=0.35时,达到460 emu/cc的最大值,矫顽力单调的从154 Oe降低到22 Oe。其原因是Zn2+离子取代A位的Fe3+离子,引起了A-O-B超交换相互作用的减弱以及A位、B位磁矩的变化。一维ZnO纳米材料由于具有独特的电学、光学、光电和压电性质以及在纳米发电机、气敏、发光二极管等领域的应用而引起人们的关注。大量的实验证明,不同形貌、不同尺寸的ZnO纳米结构具有不同的性质。可控合成不同的一维ZnO纳米结构,研究形貌、尺寸相关的性能是一项非常有意义工作。金属有机气相沉积、气相输运以及水溶液等许多方法已被用来制备ZnO纳米结构。其中物理法需要高温、复杂的仪器并且产量低,而水溶液化学法制备过程简单、能耗低并可大规模制备。到目前为止,采用Izaki的水溶液法,还没有关于合成出ZnO纳米针阵列、纳米棒阵列、方尖塔阵列以及多晶膜的报道。本论文工作的第二个创新点是采用催化法制备出了多种一维ZnO纳米结构并对其结构和性质进行了细致研究： (1)采用催化法,调节Zn(NO3)2的浓度,首次在Zn(NO3)2-DMAB溶液中制备出了ZnO纳米针阵列、纳米棒阵列以及ZnO多晶薄膜。低浓度Zn(NO3)2(2-15mM)条件下有利于得到ZnO纳米针阵列。 (2)将反应时间从1分钟延长至96小时,低Zn(NO3)2浓度条件下ZnO纳米结构依次经历了形成等轴晶粒、等轴晶粒到纳米棒、纳米棒到纳米针、纳米针的生长、纳米针到方尖塔、方尖塔到六角柱的演变过程。生长过程是由ZnO自身的晶体学特性,溶液中Zn2+离子的扩散方向以及生长热力学等因素引起的。 (3)TEM和XRD结果证明ZnO纳米结构的生长方向是0001晶体学方向。通过SEM结果估算,得出单位薄膜面积内针状ZnO纳米线阵列具有最大的表面积。XPS结果证明ZnO纳米结构表而存在Zn(OH)2和O空位的表面态。 (4)ZnO纳米针阵列具有最大的可见光发射强度,这是由于ZnO纳米针阵列表面具有最大数量的可见光发光中心。ZnO纳米针阵列同时具有最高的光催化降解甲基橙的活性。
[Abstract]:With the rapid development of modern communication technology, the miniaturization, integration and high frequency of electronic components will make the spinel ferrite thin film very useful. The development of high density vertical magnetic recording medium, thin film head, thin film transformer, film inductor, multilayer film device, biological engineering, medical diagnosis technology and magnetic drugs will be developed. The structure and magnetic properties of the spinel type ferrite depend on the properties of the doped ions, the concentration, the occupying and the preparation methods. In the preparation of the traditional ferrite thin film, the crystallization of the material needs to be carried out at high temperature (600 degrees C), making the ferrite thin film unsuitable for the substrate with poor heat resistance. Materials (such as polyacrylic, polymer particles, GaAs integrated circuits, etc.) are deposited. At present, the main mainstream method for the synthesis of spinel type ferrite thin films at low temperature is rotating spraying. However, this method has the disadvantages of complex preparation process and waste of reaction liquid, and the high pH value of solution in the process of rotating spraying is easy to generate hydrogen. The catalytic method invented by.Izaki, such as iron oxide, can overcome the difficulties mentioned above, but there are few studies on the catalytic method. This method can only be used to prepare a single Fe0.16Zn2.84O4 ferrite thin film of Fe304 thin films and components, which is unfavorable to the promotion of the catalysis.
The first innovation in this work is the preparation of NiZnCo doped spinel ferrite thin film by catalytic method and its structure and properties are carefully studied.
(1) by controlling the concentration of the reactants of Fe (NO3) 3, Zn (NO3) 2, Ni (NO3) 2, Co (NO3) 2) under the condition of 80 C, a multi component doped Ni0.11ZnxCo0.03Fe2.86-xO4 (x= 0.00,0.23,0.34,0.43 and 0.51) spinel ferrite thin film is prepared for the first time in the concentration of the reaction substance of 3, Ni (NO3) 2 and Co (NO3) 2. In the membrane, the concentration of Zn2+ ions in the preparation process is particularly critical.
(2) the Ni0.11Zn0.51Co0.03Fe2.35O4 film is composed of 40-50 nm equiaxed particles. After 1 hours of deposition, the thickness of the film reaches about 500 nm, and the surface is rough. From the lowest valley to the peak of the film, there is a 200 nm fluctuation. With the increase of the content of Zn2+ ions, the particles of the film become even and finer.
(3) XRD spectrum analysis showed that x increased from 0 to 0.51, the lattice constant increased from 8.383 A to 8.425A., and the grain size calculated by Scherrer formula was around 40 nm. With the increase of Zn2+ ion content, the Raman peak at the 680 cm-1 wave number moved and widened gradually, and the peak could be fitted into two peaks of wave numbers in 655 and 687 cm-1, and they returned to them respectively. The stretching vibration of ZnO4 and FeO4 tetrahedron shows that Zn2+ ions tend to occupy A sites.
(4) the magnetic properties of the film can be controlled by adjusting the content of Zn2+ ions to control the increase of.X. The saturation magnetization increases first and then decreases. At x=0.35, the maximum value of 460 emu/cc is reached, the coercive force is monotonously reduced from 154 Oe to 22 Oe.. The reason is that the Zn2+ ions replace the Fe3+ ions of the A bit, which leads to the weakening of the A-O- B exchange interaction and the A position and the B position magnetic field. The change of moment.
One dimensional ZnO nanomaterials have attracted people's attention due to their unique electrical, optical, photoelectric and piezoelectric properties, as well as the applications in nanoscale generators, gas sensors and light-emitting diodes. A large number of experiments have proved that different morphology and different sizes of ZnO nanostructures have different properties. The study of morphology and size dependent properties is a very meaningful work. Many methods, such as metal organic vapor deposition, gas phase transport and aqueous solution, have been used to prepare ZnO nanostructures. The physical method requires high temperature, complex instruments and low production, and the preparation process of water solution is simple, energy consumption is low and can be prepared on a large scale. So far, the aqueous solution method of Izaki has not yet been reported on the synthesis of ZnO nanoscale arrays, nanorod arrays, Pinnacle arrays and polycrystalline films.
The second innovation of this work is the preparation of a variety of one-dimensional ZnO nanostructures by catalytic method, and their structure and properties are studied in detail.
(1) using catalytic method and adjusting the concentration of Zn (NO3) 2, ZnO nanorod array, nanorod array and ZnO polycrystalline thin film are prepared in Zn (NO3) 2-DMAB solution for the first time. Under the condition of low concentration Zn (NO3) 2 (2-15mM), ZnO nanoscale array can be obtained.
(2) the reaction time was extended from 1 minutes to 96 hours, and under the low Zn (NO3) 2 concentration, the ZnO nanostructures experienced the formation of equiaxed grains, the equiaxed grains to nanorods, nanorods to nanorods, nanorods, nanobelts, square spire and six angle columns. The growth process was the crystallographic characteristics of ZnO itself, solution. The direction of diffusion of Zn2+ ions and growth thermodynamics and other factors.
(3) the results of TEM and XRD show that the direction of the growth of ZnO nanostructures is 0001 crystallographic direction. Through the SEM results, it is estimated that the maximum surface area.XPS results of the needle like ZnO nanowire arrays in the area of the unit film prove that there is a surface state of the Zn (OH) 2 and O vacancies in the ZnO nanostructure table.
(4) the ZnO nanorod array has the maximum visible light emission intensity, which is due to the maximum number of visible light luminescence center.ZnO nanorod arrays on the surface of the ZnO nanorod array with the highest photocatalytic degradation of methyl orange.
【学位授予单位】：兰州大学
【学位级别】：博士
【学位授予年份】：2010
【分类号】：TB383.2;TM277

【参考文献】