磁性元素掺杂氧化铟锡纳米结构的制备与物性研究

发布时间：2018-01-15 02:08

本文关键词：磁性元素掺杂氧化铟锡纳米结构的制备与物性研究　出处：《上海师范大学》2017年硕士论文　论文类型：学位论文

【摘要】：稀磁氧化物能在同一材料上结合半导体性与铁磁性,具有广阔的应用前景,受到了很大的关注。在氧化物基体中,氧化铟锡(indium tin oxide:ITO)基稀磁氧化物具有高可见光透过率、优异的导电性、高过渡金属离子相溶性,被认为是最有发展潜力的稀磁氧化物主基体。关于磁性元素掺杂ITO纳米颗粒的制备,在以往报道中,研究者总是采取物理方法(比如溅射)将其掺杂入氧化物中,这些方法制备的样品往往有不同程度的磁性掺杂物析出,而样品的铁磁性也有相当一部分源于此析出杂质。在本论文中,则是利用化学热分解法直接在一般空气环境下制备高质量的磁性元素掺杂ITO纳米颗粒,并利用溶胶-凝胶法制备出相应的磁性元素掺杂ITO纳米颗粒薄膜。探索了磁性元素掺杂ITO纳米结构相应的物理特性,为日后进一步开展磁性透明电极提供了实验基础。主要研究结果如下:1.利用化学热分解法制备了掺镝ITO纳米颗粒,通过X射线衍射等测定,样品中没有Dy2O3晶体被发现。掺镝TO纳米颗粒的磁矩与Dy3+的掺杂浓度有关,Dy3+掺杂浓度越高则样品中的磁矩越高。另外,在Sn4+浓度高即电子浓度高的情况下,磁化强度显著升高。这种磁性强化源于RKKY理论所预言的载流子诱导的铁磁性,说明Dy-ITO纳米颗粒中的传导电子和Dy3+中的f层电子存在着较强交换耦合作用。另外,在溶胶-凝胶法制备的薄膜上观察到了由反弱局域化效应引起的正磁致电阻变化率。Dy3+使ITO体系的产生了很强的自旋-轨道耦合。2.通过化学热分解法制备的Fe-ITO纳米颗粒和Fe-ITO纳米颗粒薄膜有很好的结晶度且没有Fe氧化物的杂项。Fe-ITO纳米颗粒薄膜中的电导模式为ES型变程跳跃电导。在低温弱场条件下,Fe-ITO纳米颗粒薄膜磁致电阻曲线出现了正磁电阻阻变化率,表明了体系中的二维电子气由于自旋散射产生了反弱局域化效应,Fe的掺入使得ITO体系中引入了一个很强的s-d耦合。
[Abstract]:Dilute magnetic oxides can combine semiconductor and ferromagnetism on the same material, so they have a wide application prospect and have attracted great attention. Indium tin oxide / ITO) based dilute magnetic oxides have high visible light transmittance, excellent conductivity and high transition metal ion compatibility. It is considered as the most promising dilute magnetic oxide matrix. The preparation of magnetic element doped ITO nanoparticles has been reported in the past. Researchers always use physical methods (such as sputtering) to doped them into the oxide, these methods of preparation of samples often have varying degrees of magnetic dopant precipitation. The ferromagnetism of the sample is also due to the precipitation of impurities. In this paper, the chemical thermal decomposition method is used to prepare high quality magnetic element doped ITO nanoparticles directly in the general air environment. The corresponding magnetic element doped ITO nanocrystalline films were prepared by sol-gel method. The physical properties of magnetic element doped ITO nanostructures were explored. The main results are as follows: 1. Dysprosium doped ITO nanoparticles were prepared by chemical thermal decomposition method and were determined by X-ray diffraction. No Dy2O3 crystal was found in the sample. The magnetic moment of dysprosium to nanoparticles was related to the doping concentration of Dy3. The higher the doping concentration of Dy 3 was, the higher the magnetic moment in the sample was. The magnetization increases significantly when the concentration of Sn4 is high, that is, the electron concentration is high. This magnetic enhancement is derived from the carrier induced ferromagnetism predicted by RKKY theory. It is concluded that there is a strong exchange coupling effect between the conduction electrons in Dy-ITO nanoparticles and the f layer electrons in Dy3. The change rate of positive magnetoresistance induced by anti-weak localization effect. Dy3 was observed on the films prepared by sol-gel method. The spin-orbit coupling of ITO system is very strong. 2. Fe-ITO nanoparticles and Fe-ITO nanoparticles films prepared by chemical thermal decomposition have good crystallinity and no FeO2. The conductance mode in the Fe-ITO nano-particle films is es type range hopping conductance, and at low temperature and weak field. The magnetoresistive curves of Fe-ITO nanocrystalline films show positive magnetoresistive resistance, which indicates that the two-dimensional electron gas in the system has anti-weak localization effect due to spin scattering. A strong s-d coupling was introduced into the ITO system with Fe doping.
【学位授予单位】：上海师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.1

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