本文關(guān)鍵詞：磁性元素?fù)诫s氧化銦錫納米結(jié)構(gòu)的制備與物性研究　出處：《上海師范大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 稀磁氧化物 化學(xué)熱分解法 載流子致鐵磁性 弱局域化 磁致電阻

【摘要】：稀磁氧化物能在同一材料上結(jié)合半導(dǎo)體性與鐵磁性,具有廣闊的應(yīng)用前景,受到了很大的關(guān)注。在氧化物基體中,氧化銦錫(indium tin oxide:ITO)基稀磁氧化物具有高可見光透過率、優(yōu)異的導(dǎo)電性、高過渡金屬離子相溶性,被認(rèn)為是最有發(fā)展?jié)摿Φ南〈叛趸镏骰w。關(guān)于磁性元素?fù)诫sITO納米顆粒的制備,在以往報道中,研究者總是采取物理方法(比如濺射)將其摻雜入氧化物中,這些方法制備的樣品往往有不同程度的磁性摻雜物析出,而樣品的鐵磁性也有相當(dāng)一部分源于此析出雜質(zhì)。在本論文中,則是利用化學(xué)熱分解法直接在一般空氣環(huán)境下制備高質(zhì)量的磁性元素?fù)诫sITO納米顆粒,并利用溶膠-凝膠法制備出相應(yīng)的磁性元素?fù)诫sITO納米顆粒薄膜。探索了磁性元素?fù)诫sITO納米結(jié)構(gòu)相應(yīng)的物理特性,為日后進(jìn)一步開展磁性透明電極提供了實驗基礎(chǔ)。主要研究結(jié)果如下:1.利用化學(xué)熱分解法制備了摻鏑ITO納米顆粒,通過X射線衍射等測定,樣品中沒有Dy2O3晶體被發(fā)現(xiàn)。摻鏑TO納米顆粒的磁矩與Dy3+的摻雜濃度有關(guān),Dy3+摻雜濃度越高則樣品中的磁矩越高。另外,在Sn4+濃度高即電子濃度高的情況下,磁化強(qiáng)度顯著升高。這種磁性強(qiáng)化源于RKKY理論所預(yù)言的載流子誘導(dǎo)的鐵磁性,說明Dy-ITO納米顆粒中的傳導(dǎo)電子和Dy3+中的f層電子存在著較強(qiáng)交換耦合作用。另外,在溶膠-凝膠法制備的薄膜上觀察到了由反弱局域化效應(yīng)引起的正磁致電阻變化率。Dy3+使ITO體系的產(chǎn)生了很強(qiáng)的自旋-軌道耦合。2.通過化學(xué)熱分解法制備的Fe-ITO納米顆粒和Fe-ITO納米顆粒薄膜有很好的結(jié)晶度且沒有Fe氧化物的雜項。Fe-ITO納米顆粒薄膜中的電導(dǎo)模式為ES型變程跳躍電導(dǎo)。在低溫弱場條件下,Fe-ITO納米顆粒薄膜磁致電阻曲線出現(xiàn)了正磁電阻阻變化率,表明了體系中的二維電子氣由于自旋散射產(chǎn)生了反弱局域化效應(yīng),Fe的摻入使得ITO體系中引入了一個很強(qiáng)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.
【學(xué)位授予單位】：上海師范大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TB383.1

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