本論文研究奈米級尺寸顆粒 Bi1-xDyxFeO（x = 0.00、0.05、0.10、3
0.15、0.20、0.30、0.40）多鐵材料的全頻反射與拉曼散射光譜。實驗 結果歸納為以下三點結論：
第一，隨摻雜鏑離子濃度增加，Bi1-xDyxFeO3 的晶格結構發生變 化：0.00 ≤ x ≤ 0.05 屬於空間群 R3c 菱形晶系結構；0.20 ≤ x ≤ 0.40 屬於空間群 pnma 正交晶系結構。光譜響應亦可依 x ＜ 0.10 與 x
＞ 0.15 區分為兩部分，其中，皆有部分振動峰隨摻雜濃度提高發生 藍移的現象，此因鏑的離子半徑（ = 0.912 Å）小於鉍離子半徑
（ = 1.030 Å），鏑離子的取代，使得離子半徑變小、鍵結能量升 高，造成拉曼峰的頻率隨摻雜濃度增加而藍移。此外，隨摻雜濃度的 提高，光譜響應明顯顯現多倍磁振子的貢獻：紅外吸收光譜中，當 x
≧ 0.30 時顯現二倍磁振子的貢獻於頻率位置約為 1700 cm-1；在拉 曼光譜中，當 x ≧ 0.15 則在 1820 cm-1 及 2930 cm-1 處顯現二倍 及三倍磁振子的貢獻，代表鏑離子的摻雜亦導致 Bi1-xDyxFeO3本身磁 性結構的改變。此因鏑離子的摻雜使得鉍鐵氧本身螺旋自旋被抑制，
同時樣品顆粒尺寸縮小至奈米級（小於自旋波波長），更加強破壞了 鉍鐵氧本身的螺旋自旋特性，磁振子的貢獻因而顯現。
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第二，隨溫度上升，BiFeO3樣品拉曼峰的強度及半高寬在尼爾溫 度（643 K）附近並未有明顯的變化發生，且頻率位置 219 cm-1 拉曼 峰隨溫度上升紅移取率與強度變化皆與文獻[46]十分相符，驗證尼爾 溫度附近自旋─聲子的耦合作用。而 Bi1-xDyxFeO3拉曼峰的強度及半 高寬在尼爾溫度附近皆未有明顯的變化發生，這代表自旋與聲子的交 互作用微弱。雖然鏑離子的摻雜使鉍鐵氧本身的螺旋自旋被抑制，造 成其磁電效應的增加，但其改變所造成的變化量不及熱擾動作用造成 的影響，同時，奈米尺寸顆粒的樣品具有表面缺陷，因此於拉曼散射 光譜中，尼爾溫度附近拉曼峰的頻率位置與半高寬並無明顯變化發生，
其變化量皆在誤差範圍內。
第三，低頻拉曼散射光譜隨鏑離子摻雜濃度的提高，顯現了擴散 響應（diffusive response），我們認為鏑離子的摻雜造成了晶格劇烈扭 曲，降低電荷的漂移率，使得 Bi1-xDyxFeO3的電性傳導屬於電荷躍遷 機制。拉曼高溫散射光譜實驗中，Bi0.85Dy0.15FeO3及 Bi0.6Dy0.4FeO3 的 擴散響應之半高寬皆隨溫度升高而變小，Bi1-xDyxFeO3 電荷彼此之間 的碰撞率降低，暗指其電性傳導愈佳化。此因樣品屬於絕緣體，隨溫 度上升其電阻變小。
由於磁振子激發對於磁性相轉變很敏感，文獻上[70]提出鉍鐵氧 樣品於低溫存在可能與自旋重新排列相關的磁性相轉變。未來，我們
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希望量測 Bi1-xDyxFeO3（x = 0.00、0.05、0.10、0.15、0.20、0.30、0.40）
低溫拉曼散射光譜與紅外光反射光譜，藉由磁振子對磁性相轉變敏感 的特性，對此部分進行更進一步的探究。
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