本文選題：鐵酸鉍 + 摻雜　； 參考：《華南理工大學(xué)》2014年碩士論文

【摘要】：多鐵性材料在某一溫度范圍內(nèi)同時(shí)具有鐵電和鐵磁性能，在新一代信息存儲(chǔ)器、傳感器和自旋電子器件等領(lǐng)域有著重要的應(yīng)用前景。鐵酸鉍（BiFeO3）是單相多鐵性代表材料之一，因其具有很高的鐵電居里溫度（Tc=830oC）和反鐵磁尼爾溫度（Tn=370oC）而備受關(guān)注。然而，在BiFeO3制備過程中通常會(huì)生成Bi2Fe4O9和Bi25FeO40等雜質(zhì)，導(dǎo)致其漏電流增大。制備單相BiFeO3材料并提高其鐵電鐵磁性能已成為國際上大研究熱點(diǎn)之一。 本論文分別采用溶劑熱法、溶膠凝膠法—水熱法、水熱法和軟化學(xué)法等化學(xué)法制備了BiFeO3及Bi1-xNdxFeO3（BNFO）、Bi1-xLaxFeO3（BLFO）納米粉體，并用掃描電鏡（SEM）、掃描電鏡能譜（EDS）、X射線衍射儀（XRD）、差熱分析儀（DTA）磁性能測試儀等分析測試手段對納米材料的尺寸、結(jié)構(gòu)、形貌及其電性能、磁性能進(jìn)行了表征。主要內(nèi)容如下： （1）首次采用乙醇-水混合溶劑作為水熱溶劑，在120℃低溫下成功地水熱合成了純BiFeO3納米粉體。在合成過程中，溶劑的成分和比例是對鐵酸鉍的生成具有重要的影響。只有當(dāng)乙醇-水比例在4:3和2:5之間時(shí)，才能在低至120℃下合成單相BiFeO3粉體。該溫度是目前合成鐵酸鉍的最低溫度。用4:3乙醇-水混合溶劑合成的BiFeO3納米粉體主要是由尺寸在50nm~150nm的顆粒組成的立方結(jié)構(gòu)。ZFC和FC磁性能測試表明，BiFeO3納米粉體在凍結(jié)溫度5K下，具有玻璃態(tài)轉(zhuǎn)化的現(xiàn)象。BiFeO3納米粉體在室溫下展現(xiàn)出鐵磁有序，者可用尺寸效應(yīng)來解釋，同時(shí)在BiFeO3樣品中也得到了電滯回線。室溫下的鐵磁有序和鐵電有序，證明了純BiFeO3晶體具有多鐵性能。 （2）采用新穎的溶膠-凝膠-水熱法合成了多鐵性Bi1-xNdxFeO3(BNFO, x=0-0.35)粉體。結(jié)果發(fā)現(xiàn)，在x≤0.25時(shí)能合成單相的Bi1-xNdxFeO3晶體，而合適濃度的KOH和NaOH分別有利于合成純的Bi1-xNdxFeO3和Bi2Fe4O9晶體。掃描電鏡結(jié)果表明BNFO晶體呈球形，其尺寸對KOH的濃度很敏感。BNFO晶體的鐵電居里溫度隨著Nd摻雜的增加而向低溫移動(dòng)。磁性能測試結(jié)果表明，隨著Nd摻雜量的增加，樣品的磁性能得到增強(qiáng)。此外，我們還討論了Bi1-xNdxFeO3晶體的形成機(jī)制。 （3）用水熱法合成了鑭摻雜的鐵酸鉍晶體（Bi1-xLaxFeO3，x=0，0.15，0.3和0.4）。在合成過程中，前驅(qū)體的成分、氫氧化鉀的濃度、水熱合成的溫度和時(shí)間，都對Bi1-xLaxFeO3的結(jié)晶和顆粒形貌發(fā)揮著重要的作用。當(dāng)x＜0.3時(shí)，可以合成純的Bi1-xLaxFeO3晶體，而且隨著La的摻入量的增加，鐵電轉(zhuǎn)變溫度從834.2℃降低至828.7℃。討論了Bi1-xLaxFeO3晶體的生長機(jī)理。而且，實(shí)驗(yàn)結(jié)果表明，，La的摻入大大的提高了剩余極化。 （4）使用酒石酸作為絡(luò)合劑，采用軟化學(xué)法合成了Bi1xNdxFeO3粉體。通過XRD、DTA、FT-IR和TEM等方法表征合成的粉體。結(jié)果表明，采用500℃就能合成結(jié)晶良好的單相Bi1xNdxFeO3粉體，其尺寸在30~50nm之間。磁性能測試表明，隨著Nd的摻入，BNFO的磁性能得到提高。當(dāng)Nd摻雜量達(dá)到0.2時(shí)，Bi1xNdxFeO3納米粉體的磁性能達(dá)到最大，此時(shí)矯頑場達(dá)Hc=15368Oe，剩余磁化強(qiáng)度Ms=0.1944emu/g，M-H回線面積達(dá)到最大。
[Abstract]:Ferroelectric and ferromagnetic properties at a certain temperature range have an important application prospect in the new generation of information memory, sensors and spintronic devices. Bismuth ferrate (BiFeO3) is one of the single-phase multi iron representative materials, because of its high ferroelectric Curie temperature (Tc=830oC) and antiferromagnetic Neal temperature (Tn= 370oC) has attracted much attention. However, in the process of BiFeO3 preparation, impurities such as Bi2Fe4O9 and Bi25FeO40 are usually generated, which leads to the increase of leakage current. The preparation of single-phase BiFeO3 material and the improvement of ferroelectric ferromagnetism have become one of the hot research topics in the world.
In this paper, BiFeO3 and Bi1-xNdxFeO3 (BNFO), Bi1-xLaxFeO3 (BLFO) nanoscale powders were prepared by solsol-gel method, sol-gel method, hydrothermal method, hydrothermal method and soft chemical method. Scanning electron microscopy (SEM), scanning electron microscopy (EDS), X ray diffractometer (XRD), differential thermal analyzer (DTA) magnetic energy tester and other analytical instruments were used in this paper. The size, structure, morphology, electrical properties and magnetic properties of nanomaterials were characterized.
(1) the ethanol water mixed solvent was used as a hydrothermal solvent for the first time, and the pure BiFeO3 nano powder was synthesized successfully at 120 C at low temperature. In the process of synthesis, the composition and proportion of the solvent have an important influence on the formation of bismuth ferrate. Only when the proportion of ethanol water is between 4:3 and 2:5, the single phase BiFeO3 can be synthesized at low to 120. The temperature is the lowest temperature for the synthesis of bismuth ferrite at present. The BiFeO3 nano powders synthesized by 4:3 ethanol water mixed solvent are mainly cubic structure.ZFC and FC magnetic properties of the particles in 50nm~150nm particles. It is shown that the BiFeO3 nano powder has the phenomenon of glass state transformation at the freezing temperature 5K, and the.BiFeO3 nano powder is in the chamber. The ferromagnetic order is displayed at the temperature, which can be explained by the size effect. At the same time, the hysteresis loop is also obtained in the BiFeO3 sample. The ferromagnetic order and the ferroelectric order at room temperature prove that the pure BiFeO3 crystal has the properties of multi iron.
(2) a novel polyferric Bi1-xNdxFeO3 (BNFO, x=0-0.35) powder was synthesized by a novel sol-gel hydrothermal method. The results showed that the single phase Bi1-xNdxFeO3 crystal could be synthesized at the x < 0.25. The suitable concentration of KOH and NaOH was beneficial to the synthesis of pure Bi1-xNdxFeO3 and Bi2Fe4O9 crystals respectively. The results of scanning electron microscopy showed that the BNFO crystal was spherical and its size was opposite. The concentration of KOH is sensitive to the ferroelectric Curie temperature of the.BNFO crystal moving to the low temperature with the increase of Nd doping. The magnetic energy test results show that the magnetic properties of the samples are enhanced with the increase of the amount of Nd doping. In addition, we also discuss the formation mechanism of the Bi1-xNdxFeO3 crystal.
(3) lanthanum doped bismuth ferrite crystals (Bi1-xLaxFeO3, x=0,0.15,0.3 and 0.4) are synthesized by hydrothermal method. In the process of synthesis, the composition of the precursor, the concentration of potassium hydroxide, the temperature and time of hydrothermal synthesis, play an important role in the crystallization and particle morphology of Bi1-xLaxFeO3. When x < 0.3, the pure Bi1-xLaxFeO3 crystal can be synthesized. With the increase of the amount of La, the transition temperature of ferroelectric decreased from 834.2 to 828.7 C. The growth mechanism of Bi1-xLaxFeO3 crystal was discussed. Moreover, the experimental results showed that the addition of La greatly increased the residual polarization.
(4) using tartaric acid as the complexing agent, Bi1xNdxFeO3 powder was synthesized by soft chemical method. The powder was characterized by XRD, DTA, FT-IR and TEM. The results showed that a good crystalline single phase Bi1xNdxFeO3 powder could be synthesized by 500 C. The size of the powder was between 30~50nm. The magnetic properties test showed that the magnetic properties of BNFO were obtained with the incorporation of Nd. When the doping amount of Nd reaches 0.2, the magnetic properties of Bi1xNdxFeO3 nano powders reach the maximum, at this time the coercive field reaches Hc=15368Oe, the residual magnetization is Ms=0.1944emu/g, and the area of the M-H return line reaches the maximum.

【學(xué)位授予單位】：華南理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TM221

【共引文獻(xiàn)】

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1 徐任信;王鈞;周靜;楊小利;;室溫磁電材料的制備與性能[J];材料導(dǎo)報(bào);2008年07期

2 于志偉;苗鴻雁;談國強(qiáng);;水熱法合成Bi_(25)FeO_(40)納米粉體的研究[J];材料科學(xué)與工藝;2009年06期

3 苗鴻雁;張瓊;談國強(qiáng);朱剛強(qiáng);;鈣鈦礦型鐵酸鉍粉體的水熱合成及表征[J];稀有金屬材料與工程;2007年S1期

4 劉運(yùn);苗鴻雁;朱剛強(qiáng);談國強(qiáng);;水熱法合成和表征有序排列BiFeO_3納米線[J];稀有金屬材料與工程;2007年S2期

5 熊銳;周忠坡;;發(fā)展中的磁電材料[J];信息記錄材料;2006年06期

6 曹東升;江洪建;胡淵;龔國斌;萬建國;;動(dòng)態(tài)法測量材料的磁電效應(yīng)[J];大學(xué)物理;2007年09期

7 裴穎;郭紅力;石維;肖定全;朱建國;;燒結(jié)溫度對CFO/PMN-PT磁電復(fù)合陶瓷性能的影響[J];電子元件與材料;2010年06期

8 聶軍武;徐國躍;蔣楠;;晶粒可控BaTiO_3-CoFe_2O_4磁電復(fù)合陶瓷制備及生長機(jī)制研究[J];功能材料;2007年02期

9 劉倩;呂麗;王燕;肖瑞娟;陳曉明;周劍平;劉鵬;宋永紅;;水熱法制備NiFe_2O_4-BaTiO_3復(fù)合材料及其電-磁性能[J];硅酸鹽通報(bào);2012年01期

10 朱仁強(qiáng);朱孔軍;裘進(jìn)浩;鄭勇;季宏麗;;表面活性劑對水熱合成摻鑭鋯鈦酸鉛陶瓷粉體物相及形貌的影響[J];硅酸鹽學(xué)報(bào);2010年04期

相關(guān)博士學(xué)位論文 前10條

1 汪川惠;Ba_(1-x)Bi_xTi_(1-y)Mn_yO_3和Bi_(5-x)La_xTi_3Fe_(1-y)Co_yO_(15)多鐵陶瓷的磁性、鐵電性以及介電性的研究[D];華中科技大學(xué);2011年

2 曲磊;多場耦合電磁彈性體的基本理論與計(jì)算方法研究[D];合肥工業(yè)大學(xué);2011年

3 劉兵;單晶鐵酸鉍的調(diào)控合成和磁性研究[D];河南大學(xué);2011年

4 陳建國;鐵酸鉍—鈦酸鉛多鐵性固溶體的摻雜改性及性能表征[D];上海大學(xué);2010年

5 張行泉;鐵酸鉍基多鐵性材料的制備與物性研究[D];哈爾濱工業(yè)大學(xué);2011年

6 張納;超磁致伸縮/壓電層狀磁電復(fù)合材料的磁電效應(yīng)研究[D];河北工業(yè)大學(xué);2011年

7 郭仁青;稀土摻雜BiFeO_3納米顆粒的制備及可見光催化性質(zhì)研究[D];蘇州大學(xué);2011年

8 馬爭爭;BiFeO_3基多鐵陶瓷的摻雜固溶及高壓改性研究[D];華中科技大學(xué);2012年

9 萬紅;TbDyFe薄膜的磁致伸縮性能及其與彈性、壓電襯底復(fù)合效應(yīng)研究[D];國防科學(xué)技術(shù)大學(xué);2005年

10 李雷;層狀電介質(zhì)復(fù)合結(jié)構(gòu)[D];浙江大學(xué);2006年

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