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    摘要铁电材料作为一类重要的电介质材料，具有较高的介电常数，显著的热释电和压电效应，广泛应用于从日常生活到尖端技术的多个领域。以铁酸铋BiFeO3为基的陶瓷材料作为一类性能优越的铁电材料，具有长程磁有序和长程电极化有序，是少数室温下同时具有铁电性和磁性的铁电材料之一。合适的A、B位掺杂可以调整铁酸铋基陶瓷的晶体结构，以获得更优秀的性能。
    本文采用快速液相烧结法成功制备了一系列掺杂配比的Bi1-xDyxFeO3（x=0-0.2）陶瓷样品。X射线衍射和拉曼光谱分析证实室温下陶瓷样品在镝（Dy）掺杂x=0-0.08时具有铁电性的三斜相，在x=0.2时完全转变为正交相，在x=0.01-0.17时两相共存。电滞回线和介电参数的测量表明适量掺入Dy能够得到饱和的电滞回线且最大极化强度在Dy掺杂x=0.1时略有提高；不同退火温度下的室温压电系数d33值表明陶瓷样品的压电性随Dy掺杂量的增加而减弱；最后，本论文通过对比实验建立陶瓷内部空位及电荷的迁徙模型，解释了快速烧结铁酸铋陶瓷的自极化现象。
    关键词  铁电体  BiFeO3基  A位Dy掺杂  快速烧结  介电性  自发极化7772
    毕业设计说明书（论文）外文摘要
    Title  The Preparation and Characterization Of Bi-site doped BiFeO3 Ceramics
    Abstract
    As an important kind of dielectric materials，ferroelectric materials  are characterized by high dielectric constant, remarkable pyroelectric and piezoelectric effects. This paper mainly describes the BiFeO3-based ceramic materials as ferroelectric. BiFeO3 is a very special ferroelectric material which has both long-range magnetic ordering and ordered long-range polarization. Its main advantage lies in its high ferroelectric Curie temperature and high magnetic transition temperature. A-site and B-site doped ceramics possess better properties via modulation of the crystal structure.
    In this paper, Bi1-xDyxFeO3 ceramic samples with a variety of components were prepared by the method of rapid liquid-phase sintering. X-ray and Raman spectra were used in analyzing the crystal structure to confirm that Bi1-xDyxFeO3 ceramics have a rhombohedral-to-orthorhombic phase transition at the Dy component of ~0.11-0.17. Ferroelectric and dielectric properties of the samples were measured ,which revealed that the introduction of Dy3+ enhanced the saturation polarization Ps and d33 values reduced with the Dy3+ content increasing. At last, two cooling methods were designed to distinguish two different models of temperature gradient and explain how bismuth vacancies, oxygen vacancies and inner strain introduce macroscopical self polarization.

    Keywords  Ferroelectric   A-site doped BiFeO3    Rapid Sintering
    Dielectric Property   Self polarization
    目次
    1  引言    2
    1.1  铁电体概述    2
    1.2  BiFeO3概述    7
    1.3  掺杂改性对BiFeO3陶瓷的性能影响    11
    1.4  本文研究的内容和意义    13
    2  Bi1-xDyxFeO3陶瓷的制备及测试    14
    2.1  制备系统与测试系统    14
    2.2  快速液相烧结法简介    15
    2.3  Bi1-xDyxFeO3陶瓷的制备工艺    17
    2.4  性能测试    18
    3  Bi1-xDyxFeO3陶瓷的结果与分析    20
    3.1  X射线衍射分析    20
    3.2  拉曼光谱分析    21
    3.3  Bi1-xDyxFeO3系列陶瓷的电学性能    23
    3.4  BiFeO3陶瓷的自发极化    27
    结论    30
    致谢    31
    参考文献    32
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