Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/16997
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dc.contributor李文新zh_TW
dc.contributor盧志權zh_TW
dc.contributor王昌仁zh_TW
dc.contributor.advisor藍明德zh_TW
dc.contributor.authorWei, Jung-Tingen_US
dc.contributor.author魏榮廷zh_TW
dc.contributor.other中興大學zh_TW
dc.date2008zh_TW
dc.date.accessioned2014-06-06T06:57:53Z-
dc.date.available2014-06-06T06:57:53Z-
dc.identifierU0005-0708200714175300zh_TW
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dc.identifier.urihttp://hdl.handle.net/11455/16997-
dc.description.abstractThe magnetic and electronic properties of the perovskite system La0.7Ba0.3Mn1-xFe xO 3 (x=0~0.3) have been investigate by measurements of magnetization ,resistivity and magnetoresistance .Powder x-ray diffraction patterns show the distance induced by Mn-site substitution is not obvious due to the similar radius of Mn an Fe .The transport properties show the resistance increases with Fe3+ increase and for x≦0.1 the insulator-metal transition temperature shifts to low temperature due to Fe not play a part in Double-exchange mechanism and suppress Mn3+/Mn4+ interaction.The resistance above the transition temperature can be fited by small polaron model. The magnetoresistance significantly enhance by Fe-doping increase.Values of temperature dependence of magnetization indicate the ferromagnetic double-exchange interation is gradually substituted by antiferromagnetic superexchange interation .The purpose of this thesis is to clear up the role functions of all elements in these compounds. Based on the knowledge of these compounds if would be helpful to control physical mechanism and improve the characteristics on prepaing their devices.en_US
dc.description.abstract本研究是針對La0.7Ba0.3MnO3利用其具有鈣態礦結構及龐磁阻現象, 藉由Fe3+離子摻雜取代Mn3+離子,對原子的取代來觀察磁性、電性和磁阻比所造成的影響。研究結果顯示,可知Mn位置Fe3+離子被取代造成的晶格扭曲不明顯,由X光繞射圖判讀顯示隨著摻雜量增加結構並沒有改變,因錳、鐵的離子半徑差異不大。而在傳導性中當x≦0.1,在低溫時,隨著溫度上升,自旋波被激發越容易受到散射,造成電阻上升,呈現金屬性;而在高溫時,隨著溫度不斷上升,被束縛的電子獲得跳躍能量越大,電阻率也開始下降,呈現絕緣性。同時利用複合極化子(composite polaron)模型和自旋相關傳導特性,來做電傳導的分析。得到Fe3+離子的摻雜增加,活化能增加,也相對應提高在零場電阻值。在磁性方面,從溫度改變的磁化強度也顯示Fe3+離子的摻雜增加,使得Mn-O-Fe反鐵磁超交換作用的總含量增加,導致鐵磁性逐漸減弱,磁矩間的作用力也相對減弱,易受熱效應影響,導致鐵磁轉換溫度的降低。所以本論文的研究在藉由元素的摻雜以釐清化合物中元素所判演的角色,進一步瞭解此材料的特性以期許將來在製造元件可以充分掌握其物理機制,同時在特性改善上有所依據。zh_TW
dc.description.tableofcontents目錄……………………………………………………………………… 1 圖表目錄………………………………………………………………3 第一章 前言…………………………………………………………… 9 1.1前言………………………………………………………………… 9 1.2研究動機及目的…………………………………………………10 第二章 簡介…………………………………………………………… 11 2.1磁性物質…………………………………………………………… 11 2.1.1磁性來源及種類………………………………………………… 11 2.1.2順磁性(Paramagnetism)…………………………………… 11 2.1.3 鐵磁性(Ferromagnetic)…………………………………………12 2.1.4反磁性(Diamagnetism)…………………………………………14 2.1.5反鐵磁性 (Anti-ferromagnetism)…………………………… 15 2.1.6亞鐵磁性(Ferrimagnetism)…………………………………… 16 2.1.7超交換作用……………………………………………………… 17 2.2龐磁阻相關理論…………………………………………………18 2.2.1龐磁阻材料-鈣態礦錳氧化物…………………………………18 2.2.2雙交換作用(Double Exchange)…………………………………19 2.2.3楊-泰勒扭曲理論(Jahn-Teller distortion)………………… 22 2.2.4複合式偏極子模型(Composite polaron model)……………24 第三章 樣品制備與實驗儀器………………………………………… 26 3.1樣品製成…………………………………………………………… 26 3.1.1 La0.7Ba0.3Mn1-xFexO3的配置(x=0.02~0.2)……………………… 26 3.1.2樣品燒結……………………………………………………… 26 3.2樣品的電性量測…………………………………………………… 28 3.2.1四點接線………………………………………………………… 28 3.2.2電性量測………………………………………………………… 29 3.3樣品的磁性量測…………………………………………………… 32 3.4x-ray粉末繞射儀(XRD量測)……………………………………… 33 第四章 實驗結果分析與討論………………………………………… 35 4.1 SEM掃描結果……………………………………………………… 35 4.2 X-ray繞射分析的結果…………………………………………… 38 4.3 樣品的磁性量測……………………………………………………44 4.4 樣品的電性量測……………………………………………………61 4.5 樣品的磁阻量測……………………………………………………74 第五章 結論…………………………………………………………… 84 文獻參考…………………………………………………………………86zh_TW
dc.language.isoen_USzh_TW
dc.publisher物理學系所zh_TW
dc.relation.urihttp://www.airitilibrary.com/Publication/alDetailedMesh1?DocID=U0005-0708200714175300en_US
dc.subject鈣鈦礦zh_TW
dc.subjectperovskiteen_US
dc.subject龐磁阻zh_TW
dc.subject雙交換作用zh_TW
dc.subject超交換作用zh_TW
dc.subject飽和磁矩zh_TW
dc.subject鐵磁性zh_TW
dc.subject自旋波zh_TW
dc.subject複合式偏極子模型zh_TW
dc.subject楊-泰勒偏極子zh_TW
dc.subject鐵磁轉換溫度zh_TW
dc.subjectcolossal magnetoresistanceen_US
dc.subjectdouble-exchange interactionen_US
dc.subjectsuperexchange interactionen_US
dc.subjectsaturation magnetizationen_US
dc.subjectferromagneticen_US
dc.subjectspin waveen_US
dc.subjectComposite polaron modelen_US
dc.subjectJahn-Teller polaronen_US
dc.subjectferromagnetic transition temperatureen_US
dc.titlestudy of physical properties in the colossal magnetoresistive Materials La0.7Ba0.3Mn1-xFexO3(x=0.02~0.2)en_US
dc.titleLa0.7Ba0.3Mn1-xFexO3(x=0.02~0.2)龐磁阻材料 物理性質之研究zh_TW
dc.typeThesis and Dissertationzh_TW
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