近年來三角晶格、籠紋晶格在自旋頓挫態系統為主要研究方向。這些晶格特有的幾何形狀使內部的自旋相互影響，而產生異常的量子相態(如自旋冰和自旋液體)。同時自旋頓挫的交互作用也是影響鐵磁材料重要關鍵因素。
　　由於特殊的磁性及具有自旋頓挫態系統的Cu3Bi(SeO3)2O2Cl受到相當大的關注。由兩個不同位置的自旋1/2之銅離子在ab面形成偽籠紋晶格並沿c軸堆疊，此材料具有各向異性的磁特性。我們利用化學摻雜(鋅、鈷和鎳)對Cu3Bi(SeO3)2O2Cl的自旋翻轉與多鐵性之研究。
　　利用固態合成法製備多晶(Cu1-xMx)3Bi(SeO3)2O2Cl (M = Zn, Co, and Ni)。使用X光繞射儀進行晶體結構分析，再利用超導量子干涉儀做磁性量測。研究發現鋅或鈷相對鎳較易被摻雜；同時，在晶格常數中摻雜鋅的材料呈非等向性膨脹，摻雜鈷的材料則是等向性膨脹。隨著鋅和鈷摻雜濃度的增加，聶耳溫度(TN = 25.6 K)變得越低，飽和磁化強度也隨著減少；在臨界磁場(Hc)中，除了摻雜鋅(0 ≤ x ≤ 0.05)變大，其他都變小。研究結果顯示，非磁性鋅摻雜的影響對Cu3Bi(SeO3)2O2Cl的超磁性轉變比磁性鈷摻雜的影響有更顯著的影響。

Investigation of spin frustration in triangular and Kagomé lattices has been active research field in the recent years. The unique geometry of these lattice promotes a spin frustration between the nearest neighbor magnetic ions that favors the highly exotic quantum phases such as spin ice, spin liquid, and spin glass phases. Indeed, this geometry induced spin frustration has a strong influence on the magnetic property even for the case of dominant ferromagnetic nearest neighbor interactions.
　　The layered spin-frustrated Cu3Bi(SeO3)2O2Cl has received considerable research attention due to its unusual magnetic and multiferroic properties. The two spin 1/2 Cu2+ ions form a layered pseudo-kagome lattice in the ab plane and this layers stacked along c direction. This unique layer structure along with spin frustration anisotropic magnetic and multiferroic properties. The present study focused on understanding the chemical doping (Zn, Co and Ni) influence on the spin-flip and multiferroic behaviors of Cu3Bi(SeO3)2O2Cl.
　　Polycrystalline (Cu1-xMx)Bi(SeO3)2O2Cl (M = Zn, Co, and Ni) samples were synthesized using solid-state reaction and characterized by X-ray diffraction (XRD), and magnetic measurements. Our studies show that either Zn or Co doping is easier than Ni doping. Variation of lattice constants with doping shows non-isotropic expansion for Zn and isotropic expansion for Co. The TN, Hc (expect doped Zn 0 ≤ x ≤ 0.05), and Ms are systematically shifted to lower temperature and reduced with Zn and Co doping. Our results suggest that the effect of non-magnetic Zn doping has a more significant influence on the metamagnetic transition of Cu3Bi(SeO3)2O2Cl than the effect of magnetic Co doping.

致謝 i
論文摘要 ii
Abstract iii
目錄 v
圖目錄 viii
第一章 簡介 1
1-1多鐵性介紹 1
1-2幾何自旋頓挫態系統 6
1-3 Cu3Bi(SeO3)2O2Cl晶體結構與物理特性簡介 9
1-4 研究動機 13
第二章 實驗儀器 16
2-1 X-Ray繞射儀 16
2-2 磁性量測儀器 18
2-2-1 超導量子干涉磁量儀 18
2-2-2 磁性量測方法 24
第三章 實驗結果與討論 27
3-1 Cu3Bi(SeO3)2O2Cl樣品製備 27
3-2 Cu3Bi(SeO3)2O2Cl的X-Ray繞射分析 32
3-3 X-Ray繞射分析 35
3-3-1 (Cu1-xZnx)3Bi(SeO3)2O2Cl的X-Ray繞射分析 35
3-3-2 (Cu1-xCox)3Bi(SeO3)2O2Cl的X-Ray繞射分析 40
3-3-3 (Cu1-xNix)3Bi(SeO3)2O2Cl的X-Ray繞射分析 42
3-4 磁性量測分析 44
3-4-1 (Cu1-xZnx)3Bi(SeO3)2O2Cl磁性量測分析 44
3-4-2 (Cu1-xCox)3Bi(SeO3)2O2Cl磁性量測分析 48
3-4-3 (Cu1-xNix)3Bi(SeO3)2O2Cl磁性量測分析 52
第四章 結論 53
參考文獻 55

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