本文選題：鐵酸鉍薄膜　切入點(diǎn)：摻雜　出處：《燕山大學(xué)》2015年碩士論文

【摘要】：鐵酸鉍作為一種典型地在室溫下同時(shí)具有鐵電性和鐵磁性的單相多鐵材料,其在理論上具有較高的極化強(qiáng)度,因而成為多鐵材料中的研究重點(diǎn)。本文應(yīng)用溶膠凝膠法制備鐵酸鉍薄膜,并對(duì)其進(jìn)行了摻雜改性研究。采用X射線衍射、掃描電鏡等分析手段來(lái)研究薄膜的結(jié)構(gòu)變化,并結(jié)合介電性能、鐵電性能和鐵磁性能等確定適宜摻雜量。首先研究了乙二醇甲醚和冰乙酸為溶劑的條件下,純相鐵酸鉍薄膜的最佳制備工藝。結(jié)果表明:當(dāng)鐵酸鉍薄膜的退火方式為層層退火、退火溫度為550°C、退火時(shí)間為9 min、層數(shù)為12層時(shí),BFO薄膜的結(jié)晶性最好。此時(shí)薄膜與基片具有清晰的界面,薄膜的厚度約為400 nm。適量的La摻雜可以使薄膜的晶體結(jié)構(gòu)由三方系轉(zhuǎn)變?yōu)檎幌?同時(shí)細(xì)化晶粒尺寸。8%La摻雜具有最大的剩余極化強(qiáng)度。Co摻雜不能改變薄膜的晶體結(jié)構(gòu),但是可以降低顆粒尺寸,Co的摻雜可以明顯提高薄膜的鐵磁性,8%的Co摻雜剩余磁化強(qiáng)度最大,為0.21 emu/g。在A位La摻雜量為8%的條件下,Co的摻雜卻可以使薄膜的晶體結(jié)構(gòu)發(fā)生改變,薄膜的漏電流密度隨著Co含量的增加先減少后增大,最小的漏電流密度為3.5×10-4 A/cm2,薄膜最大的剩余極化強(qiáng)度和剩余的磁化強(qiáng)度分別為4.04μC/cm2和0.36 emu/g,但是薄膜的電滯回線由于漏電流較大,仍不飽和。在A位8%La和B位8%Co的條件下,Ba的摻雜使薄膜的晶體結(jié)構(gòu)由三方系轉(zhuǎn)變?yōu)樗姆较�。由于薄膜的漏電流相�?duì)于La和Co雙摻雜降低了三個(gè)數(shù)量級(jí),因而得到了比較完整的電滯回線,薄膜最大的剩余極化強(qiáng)度和剩余的磁化強(qiáng)度分別為4.04μC/cm2和0.36 emu/g。
[Abstract]:Bismuth ferrite as a typical at room temperature and ferroelectric ferromagnetic multiferroic material, which has high in theory of polarization, and thus become the focus of research in multiferroic materials. The preparation of bismuth ferrite thin films by sol-gel method, and has carried on the modification of doping by X ray diffraction, the structure changes of SEM to study film, combined with the dielectric properties, ferroelectric properties and ferromagnetic properties to determine the optimum doping amount. Firstly, ethylene glycol methyl ether and acetic acid as solvent, the optimum preparation process of pure bismuth ferrite thin film. Show that the annealing method when bismuth ferrite thin film layers for annealing, annealing temperature was 550 C, the annealing time is 9 min and the 12 layer, the crystallinity of BFO films. The best film and the substrate has a clear interface, the film thickness is about 400 nm . the amount of La doping can make the crystal structure of the films changed from three party system for orthogonal system of fine grain size, while.8%La doped crystal structure with the remnant polarization of.Co doped thin films can not be the biggest change, but can reduce the particle size, the doping of Co can significantly improve the high magnetic thin film, 8% Co residual doping the maximum magnetization is 0.21, emu/g. is 8% in the condition of A La doping, Co doping could make the crystal structure of the films changed, the film leakage current density with the increase of Co content decreased first and then increased, the minimum leakage current density is 3.5 * 10-4 A/cm2, the largest remanent polarization film and the residual magnetization were 4.04 C/cm2 and 0.36 emu/g, but the thin film hysteresis loop due to the large leakage current, is still not saturated. In A 8%La and B 8%Co under the condition that the crystal structure of Ba doped thin films by The three party system is transformed into tetragonal system. Because the leakage current of the thin film is reduced by three orders of magnitude relative to La and Co double doping, a relatively complete hysteresis loop has been obtained. The maximum residual polarization strength and the remaining magnetization of the film are 4.04 C/cm2 and 0.36 emu/g. respectively.

【學(xué)位授予單位】：燕山大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：TQ135.32;TB383.2

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