Ca1-xSrx(Mg1/3Nb2/3)O3系統之結構與微波介電性質
Ca1-xSrx(Mg1/3Nb2/3)O3系統之結構與微波介電性質
Ca1-xSrx(Mg1/3Nb2/3)O3系統之結構與微波介電性質
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圖七則顯示了 Ca0.9Sr0.1(<strong>Mg1</strong>/<strong>3Nb2</strong>/3)O3之<br />
TEM明視野影像 (bright-field image) 及選區電<br />
子 繞 射韗 圖 (selected-area electron diffraction,<br />
SAED),從明視野影像中,我們靽可以清楚看<br />
到有序區域成長時頗,有序區域與母相(matrix)<br />
之間所形成的反相邊界(antiphase boundary,<br />
APB);圖中亦可看到因釋放氧頿八面體傾斜所<br />
造成之應力而形成的ferroelastic boundary;而<br />
SAED主要顯示出B-site陽離子以1:2有序排<br />
列之繞射韗點,且在基本繞射韗點之間亦發現因<br />
不同陽離子大小之離子取代所造成的微弱韪繞<br />
射韗點。<br />
圖七 Ca0.9Sr0.1(<strong>Mg1</strong>/<strong>3Nb2</strong>/3)O3之穿透式電子顯<br />
微鏡明視野影像、SAED與繞射韗點說明。<br />
四、結論<br />
在B-site以1:2劑量比合成的複合鈣鈦礦<br />
系統中,我們靽可以藉由拉曼光譜儀與穿透式<br />
電子顯微鏡作為輔助工具,讓我們靽更能清楚<br />
瞭解,當A-site陽離子位置以不同大小之陽離<br />
子進行取代時頗,B-site有序程度與有序區域成<br />
長的影響,以及對B-site陽離子為中心的氧頿八<br />
面體變化與微結構之間的關係,進而與其微<br />
波介電性質建立起關聯性。<br />
誌謝 誌謝 感謝中山大學貴儀中心王良珠小姐於<br />
TEM分析上的幫助。<br />
參考文獻<br />
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