文化大學機構典藏 CCUR:Item 987654321/5937
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    jsp.display-item.identifier=請使用永久網址來引用或連結此文件: https://irlib.pccu.edu.tw/handle/987654321/5937


    题名: 鋇鈦氧化合物系統之化學摻雜對微波性質的影響
    Study the microwave property of BaTiO3 compounds system by chemical doping
    作者: 王博彥
    贡献者: 材料科學與奈米科技研究所
    关键词: 六方晶鈦酸鋇
    摻雜鎵之鈦酸鋇
    微波近場顯微鏡
    拉曼光譜
    日期: 2007
    上传时间: 2010-07-05 10:30:55 (UTC+8)
    摘要: 本實驗中探討正方晶鈦酸鋇與六方晶鈦酸鋇之介電性質，因鈦酸鋇需在低氧壓或摻雜低於四價金屬元素取代鈦才能形成六方晶結構，故選擇在鈦酸鋇系統中摻雜鎵(3+)與鋯(4+)做為探討六方晶與正方晶鈦酸鋇之性質研究。
    經由XRD分析，及Rietveld法模擬結果，可知樣品均為單一相，且摻雜鎵之鈦酸鋇為六方晶結構，空間群為P63/mmc，而鈦酸鋇與摻雜鋯之鈦酸鋇為正方晶結構，空間群屬於P4mm，然而在摻雜鎵的樣品中，當燒結超過1400℃後有巨大液相燒結相產生。
    從微波性質來說，摻雜鋯之鈦酸鋇Qxf値隨體積增加而增加，摻雜鎵之鈦酸鋇，Qxf値隨體積增加而減少。由EMP之結果可知，摻雜鋯之鈦酸鋇平均K值較鈦酸鋇高，摻雜10％鋯之鈦酸鋇的K值分佈最平均，晶粒成長較明顯，造成Qxf為最高的原因。摻雜鎵之鈦酸鋇平均K值較鈦酸鋇低，摻20％後明顯的K值下降，且發現巨大液相區域的K值，較其他鄰近區域的K值高。
    由室溫的拉曼分析，鈦酸鋇與摻雜鋯的樣品中305cm-1與720cm-1為t-BaTiO3所具有的特有吸收，是在居里溫度時作相轉換時所產生的，且頻率隨著Zr的摻雜量增加有逐漸下降趨勢。摻雜鎵之鈦酸鋇實驗結果根據文獻的比對，在74cm-1的mode為E2g，154cm-1與218cm-1的mode為E1g，106cm-1、493cm-1、636cm-1與806cm-1的mode為A1g，這些為六方晶結構所具有的振動模式，且頻率隨著Ga摻雜量增加有逐漸下降趨勢。
    In this thesis, we study the dielectric properties of tetragonal phase and hexagonal phase of BaTiO3 systems. Because the hexagonal phase of BaTiO3 structure can be stable at low Oxygen sintering condition or doping lower then 4+ valences ionic on Ti-site. In this work, we study the dielectric properties of Zr-doping and Ga-doping of BaTiO3 systems, which are tetragonal structure and hexagonal structure, respectively.
    All samples are analysed by powder X-ray diffraction, which are single-phase. Based on the “Rietveld profile-fitting method”, the all Ga-doping compounds are the same symmetric space group (P63/mmc) and all Zr-doping compounds are the same symmetric space group (P4mm). Although the Ga-doping samples can form the hexagonal structure, but the samples is existence anomaly giant phase when the sintering temperature is over 1400℃.
    The microwave property was showed that the Qxf values of Zr-doping samples are increasing with unit cell volume increasing and the Qxf value of Ga-doping samples are decreasing with Ga-doping level increasing. The Evanescent Microwave Microscope (EMP) were analyzed the microstructure and dielectric properties of anomaly giant phase, which is showed the larger K values in this region. The result of EMP are consistent the result of resonant cavity method.
    Raman spectra of tetragonal phase of BaTiO3 systems are showed the prominent peaks at ~305cm-1 and ~720cm-1, which is due to phase transition of Curie temperature. The Raman shifters of Zr-doping compounds are decreasing with the Zr-doping increasing. Raman spectra of all Ga-doping samples, which appear the E2g mode (74cm-1), E1g mode (154cm-1 and 218cm-1) and A1g mode (106cm-1, 493cm-1 ,636cm-1 and 806cm-1) and those modes are owned to hexagonal structure BaTiO3 systems . The Raman shifters of Ga -doping compounds are decreasing with the Ga -doping increasing.
    显示于类别:[化學工程與材料工程學系暨碩士班] 博碩士論文

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