本論文是以摻雜不同濃度ZnO的鈮酸鋰晶體,使用HP4194A阻抗分析儀,在溫度範圍100◦C~600◦C,頻率變化100Hz~40MHz的交流電作用下,沿著其c軸量測其阻抗值。我們從阻抗數據資料中,求得導電率隨溫度、頻率的變化關係,進而求得導電活躍能,並求得摻雜氧化鋅的濃度和導電活躍能的變化。
我們也求得介電常數隨溫度、頻率的變化關係,進而求得摻雜氧化鋅的濃度和介電常數的變化。並透過M(electric modulus)的表示法求得晶體的弛豫活躍能,以求得摻雜氧化鋅的濃度和弛豫活躍能的變化,藉此希望能夠了解晶體在摻雜不同濃度氧化鋅的導電和介電特性的變化。
我們發現樣品在外加交流電作用下,同時存在有導電離子的移動和電偶極的影響。在高溫低頻的狀況下,離子的貢獻較突顯;相對地,在低溫高頻的狀況下,電偶極的貢獻才較能觀察得到。
我們將樣品對交流電下的反應採用等效電路進行模擬,以希望更加地了解離子的移動和電偶極的變化對導電和介電特性的影響,進而探討氧化鋅的添加對鈮酸鋰晶體所造成的影響。
我們分析樣品的直流導電活躍能Ea、導電率σ、介電常數ε、介電損耗因子tan δ和弛豫活躍能Em隨著滲雜ZnO的濃度變化關係,發現所得的變化結果在濃度5~6 mole%和濃度7~8 mole%時出現轉折點,故我們推測當摻雜不同濃度的氧化鋅時,在5mole%之前和5mole%~7.5mole%及7.5mole%之後有著不同的影響。
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