在微波介電材料中，本研究探討兩種系統之結構與性質 :
(1)複合鈣鈦礦結構 Ba1-xCax(Mg1/3Nb2/3)O3 材料系統：本研究針對此固溶系統做詳盡的晶體結構以及基本介電性質分析，發現到 BCMN 系統之介電性質表現與微結構和晶體結構上有相當程度的關連。以晶體結構來看，而介電常數值與晶格內八面體扭曲情形相關，八面體扭曲程度低，離子可位移的空間自由度增大，可使介電常數增加。此外，B-site 1:2 之結構有序化程度隨著 Ca2+ 進入結構中而序化度提高，對於 Qf 而言，除了受本身材料因素外，有序化結構雖可幫助 Q 值提升，然而第二相產生與低燒結體密度皆會使量測的 Q 值下降。此外，由於鈣離子的添加造成晶格常數的縮減，使單位晶胞減小，平均而言，原子間的距離靠近，原子產生非調和震盪效應將主導 τε 趨向負值，使得 添加 Ca2+ 後的 BCMN 系統之 τf 值逐漸往正值增加。
(2)Ti-O 與 Ba-Ti-O 系統：Ba-Ti-O 系統用在微波範圍時，其組成主要偏向高TiO2含量的成分，而穩定相者只有 BaTiO3、Ba6Ti17O40、Ba4Ti13O9、BaTi4O9 及 Ba2Ti9O20。本研究依照 Ti/O 計量比變化，利用八面體共用方式與結構間的關係，討論結構對於介電性質之影響。

　　研究結果顯示，鈦氧及鋇鈦氧化合物接隨著 Ti/O 計量比例增加而使八面體共用程度上升，共用程度多寡影響該化合物之堆積密度，且當八面體相繫情形較多者，每個鈦氧之鍵結強度較弱，陽離子能量不穩定，越容易偏離八面體中心位置，造成鈦氧八面體之結構扭曲。Ba-Ti-O 化合物中，隨著 Ti/O 比值提升，八面體共用情形有由鈣鈦礦結構轉變為金紅石相結構的趨勢。

　　此外，Ba/Ti 比值也隨著下降，八面體共用越多，鋇離子越少，結構中容納鋇離子的空隙越大，使鋇離子偏移或共角八面體產生tilt。當鈦氧八面體陽離子偏離中心位置或共角八面體tilt，皆可能使八面體扭曲或造成鋇離子的移位，使結構產生極化，影響鋇鈦氧結構之介電性質。

　In the microwave ceramic material, we focus on two types of dielectric systems and discuss their structures and properties, respectively.
(1)Complex perovskite structure of Ba1-xCax(Mg1/3Nb2/3)O3 system: As far as we're concerned, the microstructure and crystal structure considerably influence the dielectric properties of BCMN system. In view of crystal structure, the dielectric constant is associated with the distorted octahedra in the unit cell, the lower degree of distorted octahedra, the more free space for ions displacement which will result in the increasing dielectric constant. Besides, Ca2+ could be an effective dopant for the ordering degree. The quality factor of ratio 1:2 perovskite ceramics which is very sensitive to the B-site cation ordering could be improved as the degree of order increases. Nevertheless, the second phase and low relative density of sintered bulk would both decrease quality factor. The unit cell parameters decreased due to the contents of Ca2+ increased promote the τf increased.
(2)Ti-O and Ba-Ti-O system: The stable phase of Ti-rich of Ba-Ti-O compounds, such as BaTiO3, Ba6Ti17O40, Ba4Ti13O9, BaTi4O9, and Ba2Ti9O20 are more useful in microwave ceramic material. According to variation of Ti/O ratio, we found out the relationship between connected types of Ti-O octahedra and their dielectric properties.
　With the increasing of Ti/O ratio , more octahedra connected to each other. When this happened, the center of cation ion has higher potential energy to deviate from the center, then the distorted octahedra formed. So with the Ti/O ratio increased, The type of shared octahdera tends to transform from perovskite-like structure to rutile-like structure.
　Besides, with Ba/Ti ratio decreased, fewer Ba2+ ions with more octahedra connection cause the displacement of Ba ions and form octahedral tilt in the meantime due to more free space around. The displacement of center ion in octahedra and tilted octahedra also causes octahedral distortion and results in polarization which gives better dielectric properties.

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