跳到主要內容

臺灣博碩士論文加值系統

(100.28.0.143) 您好!臺灣時間:2024/07/14 21:10
字體大小: 字級放大   字級縮小   預設字形  
回查詢結果 :::

詳目顯示

我願授權國圖
: 
twitterline
研究生:劉彥男
研究生(外文):Yen-Nan Liu
論文名稱:Ba2SmNbXMo1-XO6 氧化物(X=1, 0.9, 0.5, 0.4, 0.3, 0.2, 0.1)之介電性質研究
論文名稱(外文):Dielectric Response of Ba2SmNbxMo1-XO6 (X=1, 0.9, 0.5, 0.4, 0.3, 0.2, 0.1)
指導教授:陳政維陳政維引用關係
指導教授(外文):Jenq-Wei Chen
口試委員:張慶瑞林金福
口試委員(外文):Chang, Ching-RayKing-Fu- Lin
口試日期:2013-07-08
學位類別:碩士
校院名稱:國立臺灣大學
系所名稱:物理研究所
學門:自然科學學門
學類:物理學類
論文種類:學術論文
論文出版年:2013
畢業學年度:101
語文別:英文
論文頁數:64
中文關鍵詞:雙鈣鈦礦反磁轉變多鐵材料介電系數
外文關鍵詞:Double peroskitesDielectric Response
相關次數:
  • 被引用被引用:0
  • 點閱點閱:150
  • 評分評分:
  • 下載下載:0
  • 收藏至我的研究室書目清單書目收藏:0
對於過渡元素鈮(Nb)和鉬(Mo)來說,兩者擁有相當接近的離子半徑
(Nb=0.69 A, Mo+4=0.68 A, Mo+6=0.65 A) ,此兩元素所形成之雙鈣鈦礦系統
(Ba2SmNbO6, Ba2SmMoO6)在晶體結構上都屬於正方晶系(Cubic structure) (Ba2SmNbO6 :a=7.463 A, Ba2SmMoO6 : a=8.2 A ),晶體常數也相近,以容忍因子(tolerance factor)角度來看,此二系統各離子在結構上之排列應是相當類似,但在介電係數,磁性,結構相變的行為卻截然不同。Ba2SmNbO6 之介電係數在20k~300k只在180~200間變化,晶體結構從20k~400k都是正方晶系,從2k~400k此系統都是順磁性; 然而Ba2SmMoO6之介電系數卻可到達104之最大值,且在TN=130k,磁性從反磁轉變為順磁,從文獻得知此為ㄧJahn – Teller效應造成之反鐵相變,且因其相變溫度對應到ㄧ個在tan δ 圖的峰值,Ba2SmMoO6應是ㄧ多鐵材料(Multiferroics)。為了瞭解造成此巨大差異之背後機制,本研究製備Ba2SmNbxMo1-XO6 (X=0, 0.1, 0.2, 0.3, 0.4, 0.5,0.9,1)摻雜系統,透過固態化學反應法,不同之燒結溫度,退火過程以及不同通氣鍛燒時間等製程以控制氧化程度,藉由X-ray粉末分析,接著以溫度和頻率作變數量測介電常數(ε’),介電損失(tan δ),複數modulus (M, M)來分析這些氧化物之行為。


The synthesis, characterization and dielectric properties of the polycrystalline rare earth oxides Ba2SmNbXMo1-XO6 compounds were investigated. Powder X-ray diffraction patterns show that all these samples are single phase without any impurity. The dielectric properties of these compounds were studied in the frequency range from 20 Hz to 1 MHz between 20 K and 320 K. The Ba2SmNbXMo1-XO6 samples exhibit a high dielectric permittivity (ε’~104)at room temperature with frequency dispersion. The corresponding tanδ(T) curves exhibit two relaxations. The peak temperature TP of tanδ shifts to a higher temperature as the frequency increases in both relaxations, indicating thermally activated relaxation. The overall behavior of high temperature ε’
and tanδ is similar to that observed in giant dielectric constant materials. The observed giant dielectric response was explained in terms of internal (grain boundary) barrier layer capacitance (IBLC) effect. Complex modulus analysis was used to distinguish the grain and grain boundary resistance in all compositions. The observed results may provide a better understanding of the dielectric properties of the Ba2SmNbXMo1-XO6 system, and might be extended to advanced applications.


誌謝 i
摘要 ii
Abstract iii
Table of Contents iv
List of Pictures v
Chapter 1 Introduction 1
Chapter2 General Background 4
a.Complex Permittivity 4
b. The Mechanism of Polarization 6
c. Debye Equations 9
d. Arrhenius law 11
Chapter 3 Experimental Details 12
A. Sample Preparation 12
a.Ba2SmNbO6 12
b.Ba2SmNbXMo1-xO6 13
B. X-ray diffraction 15
C. Dielectric Properties Measurement 16
D. Jahn – Teller Effect 17
Chapter 4 Result and discussion 18
a. Ba2SmNbO6 18
b. Ba2SmNb0.9Mo0.1O6 22
c. Ba2SmNb0.5Mo0.5O6 28
d. Ba2SmNb0.4Mo0.6O6 35
e. Ba2SmNb0.3Mo0.7O6 43
f. Ba2SmNb0.2Mo0.8O6 47
g. Ba2SmNb0.1Mo0.9O6 54
Chapter 5 Conclusion 60
References 63


1. C.N.R. Rao and B. Raveau. Colossal Magnetoresistance, Charge Ordering and
Related Properties of Manganese Oxides (1998)
2. D.Y. Chen, F. Z. Chien, D.C. Lin, J.L.Tseng, S.R. Sheet, MJ Wang, and M.K. Wu, Physics C (1997)
3. M. T. Anderson, K. B. Greenwood, G. A. Taylor, and K. R. Poeppelmeier, Elsevier Science Ltd. (1994)
4. N. Inoue, and Y. Zou, Physics of Solid State Ionics (2006)
5. W. Prellier, M. P. Singh and P. Murugavel, J. Phys.: Condens. Matter 17 (2005) R803–R832
6. K.Henmi, Y. Hinatsu, and J. of Solid State Chemistry 148, 353-360 (1999)
7. E. J. Cussen, D. R. Lynham, and J. R. Chem. Mater. 2006, 18, 2855-2866
8. H. Jahn and E. Teller (1937). Series A, Mathematical and Physical Sciences (1934-1990) 161 .
9. Hewlett-Packard Inc., Basics of Measuring the Dielectric Properties of Materials,
Application Note 1217-1.
10. D. C. Sinclair F. D. Morrison, and A. R. West, J. Am. Ceram., Soc. 84, 31 (2001)
11. Galasso, F. Darby, W. Journal of Physical Chemistry (1962) 66, 131-132
12. Charles P. Smyth, Dielectric Behavior and Structure, Mcgraw-Hill Book company, INC. (1955)
13. D. C. Sinclair, and A. R. West, J. Appl. Phys. 66, 3850 (1989)
14. Yan-Zhen Wei, and S. Sridhar, J. Chem. Phys. 99, 3119 (1993)
15. Guanghan Cao1, Lixin Feng and Cao Wang, J. Phys. D: Appl. Phys. 40 (2007) 2899–2905


QRCODE
 
 
 
 
 
                                                                                                                                                                                                                                                                                                                                                                                                               
第一頁 上一頁 下一頁 最後一頁 top
無相關論文