本文選題：尖晶石型鐵氧體 + 氧化鋅��； 參考：《蘭州大學(xué)》2010年博士論文

【摘要】： 隨著現(xiàn)代通訊技術(shù)的迅猛發(fā)展,電子元器件的小型化、集成化、高頻化必將使尖晶石型鐵氧體薄膜大有用武之地。高密度垂直磁記錄介質(zhì)、薄膜磁頭、薄膜變壓器、薄膜電感器,多層膜器件以及生物工程、醫(yī)療診斷技術(shù)、磁性藥物的發(fā)展將進(jìn)一步加快鐵氧體薄膜研究的步伐。尖晶石型鐵氧體的結(jié)構(gòu)和磁性質(zhì)取決于摻雜離子的自身特性、濃度、占位以及制備方法。傳統(tǒng)的鐵氧體薄膜制備工藝中,材料的晶化需要在高溫下進(jìn)行(600℃),使得鐵氧體薄膜不適合在耐熱性較差的基底材料(如聚脂膜、聚合物顆粒、GaAs集成電路等)上沉積。目前低溫合成尖晶石型鐵氧體薄膜的主流方法是旋轉(zhuǎn)噴涂法,但是這一方法存在制備過程復(fù)雜、浪費(fèi)反應(yīng)液等缺點(diǎn),而且旋轉(zhuǎn)噴涂法制務(wù)樣品過程中溶液pH值較高,很容易優(yōu)先生成氫氧化鐵之類的沉淀物。Izaki發(fā)明的催化法可以克服上述困難,但是有關(guān)催化法的研究比較少,該方法目前僅能用來制備Fe304薄膜和成份單一的Fe0.16Zn2.84O4鐵氧體薄膜,這對催化法的推廣是不利的。 本論文工作的第一個(gè)創(chuàng)新點(diǎn)是采用催化法制備出了NiZnCo摻雜的尖晶石型鐵氧體薄膜并對其結(jié)構(gòu)和性質(zhì)進(jìn)行了細(xì)致研究： (1)采用催化法,在80℃條件下,通過控制Fe(NO3)3、Zn(NO3)2、Ni(NO3)2、Co(NO3)2反應(yīng)物的濃度,首次在硝酸鹽和二甲基胺硼烷(DMAB)溶液中制備出了多組份摻雜的Ni0.11ZnxCo0.03Fe2.86-xO4(x=0.00、0.23、0.34、0.43和0.51)尖晶石型鐵氧體薄膜。Zn2+離子易于沉積入薄膜中，，制備過程中控制Zn2+離子的濃度尤為關(guān)鍵。 (2)Ni0.11Zn0.51Co0.03Fe2.35O4薄膜是由40-50 nm的等軸顆粒組成。薄膜沉積1小時(shí)后,膜厚達(dá)到500 nm左右,表面較粗糙,從薄膜表面的最低谷到最高峰有200 nm的起伏。隨著Zn2+離子含量的增加,組成薄膜的顆粒變得均勻細(xì)小。 (3)XRD譜分析表明,x從0增加到0.51,點(diǎn)陣常數(shù)從8.383 A增大到8.425A。由Scherrer公式計(jì)算出的晶粒尺寸在40 nm左右。隨著Zn2+離子含量的增加,680 cm-1波數(shù)處的Raman峰發(fā)生了移動(dòng)而且逐漸寬化,該峰可擬合為波數(shù)在655和687 cm-1的兩個(gè)峰,他們分別歸屬于ZnO4和FeO4四面體的伸縮振動(dòng),證明Zn2+離子傾向于占據(jù)A位。 (4)薄膜的磁性可以通過調(diào)節(jié)Zn2+離子含量來控制。x增加,飽和磁化強(qiáng)度先增大后減小,在x=0.35時(shí),達(dá)到460 emu/cc的最大值,矯頑力單調(diào)的從154 Oe降低到22 Oe。其原因是Zn2+離子取代A位的Fe3+離子,引起了A-O-B超交換相互作用的減弱以及A位、B位磁矩的變化。 一維ZnO納米材料由于具有獨(dú)特的電學(xué)、光學(xué)、光電和壓電性質(zhì)以及在納米發(fā)電機(jī)、氣敏、發(fā)光二極管等領(lǐng)域的應(yīng)用而引起人們的關(guān)注。大量的實(shí)驗(yàn)證明,不同形貌、不同尺寸的ZnO納米結(jié)構(gòu)具有不同的性質(zhì)�？煽睾铣刹煌囊痪SZnO納米結(jié)構(gòu),研究形貌、尺寸相關(guān)的性能是一項(xiàng)非常有意義工作。金屬有機(jī)氣相沉積、氣相輸運(yùn)以及水溶液等許多方法已被用來制備ZnO納米結(jié)構(gòu)。其中物理法需要高溫、復(fù)雜的儀器并且產(chǎn)量低,而水溶液化學(xué)法制備過程簡單、能耗低并可大規(guī)模制備。到目前為止,采用Izaki的水溶液法,還沒有關(guān)于合成出ZnO納米針陣列、納米棒陣列、方尖塔陣列以及多晶膜的報(bào)道。 本論文工作的第二個(gè)創(chuàng)新點(diǎn)是采用催化法制備出了多種一維ZnO納米結(jié)構(gòu)并對其結(jié)構(gòu)和性質(zhì)進(jìn)行了細(xì)致研究： (1)采用催化法,調(diào)節(jié)Zn(NO3)2的濃度,首次在Zn(NO3)2-DMAB溶液中制備出了ZnO納米針陣列、納米棒陣列以及ZnO多晶薄膜。低濃度Zn(NO3)2(2-15mM)條件下有利于得到ZnO納米針陣列。 (2)將反應(yīng)時(shí)間從1分鐘延長至96小時(shí),低Zn(NO3)2濃度條件下ZnO納米結(jié)構(gòu)依次經(jīng)歷了形成等軸晶粒、等軸晶粒到納米棒、納米棒到納米針、納米針的生長、納米針到方尖塔、方尖塔到六角柱的演變過程。生長過程是由ZnO自身的晶體學(xué)特性,溶液中Zn2+離子的擴(kuò)散方向以及生長熱力學(xué)等因素引起的。 (3)TEM和XRD結(jié)果證明ZnO納米結(jié)構(gòu)的生長方向是0001晶體學(xué)方向。通過SEM結(jié)果估算,得出單位薄膜面積內(nèi)針狀ZnO納米線陣列具有最大的表面積。XPS結(jié)果證明ZnO納米結(jié)構(gòu)表而存在Zn(OH)2和O空位的表面態(tài)。 (4)ZnO納米針陣列具有最大的可見光發(fā)射強(qiáng)度,這是由于ZnO納米針陣列表面具有最大數(shù)量的可見光發(fā)光中心。ZnO納米針陣列同時(shí)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.
【學(xué)位授予單位】：蘭州大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2010
【分類號】：TB383.2;TM277

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本文編號：2102578