在凝態物理領域中，發現新的磁狀態是個很有潛力的研究項目，而skyrmion狀態(A-phase)是其中一種磁矩會形成漩渦狀排列的新穎磁狀態。此現象最先被發現於金屬化合物MnSi，之後才被發現於絕緣體Cu2OSeO3中，此種非比尋常的磁有序現象，會出現於特定之溫度與磁場範圍下。
現今，我們研究著重於Cu2OSeO3系統中，非磁性元素對skyrmion相之摻雜效應。我們對使用固態合成法製成之多晶樣品 —— (Cu1-xZnx)2OSeO3 ( x = 0, 0.01, 0.02, 0.04, 0.06, 0.08, 0.10, 0.15, 0.20)做了XRD檢測與磁性量測。此樣品的晶格結構屬於非對稱中心立方體P213，XRD檢測結果顯示，當x≦0.20時，晶格常數變化與鋅摻雜量會呈線性趨勢，說明鋅成功取代銅，摻雜於樣品中。隨著鋅摻雜量增加，居里溫度(TC)與磁化強度有逐漸下降趨勢，顯示鐵磁相逐漸被抑制，此外，我們發現在0.02<x<0.20時，會出現另一個磁相，且其磁轉變也是隨著鋅摻雜量增加往低溫區位移。所有樣品都透過不同溫度下之交流磁化率掃磁場(χˈac-H)的量測，進而得到一系列H-T相圖。我們將會探討摻雜效應對skyrmion 樣品Cu2OSeO3之A-phase有何影響。

There is a considerable interest growing on the discovery of new magnetic state in the field of condensed matter physics. Skyrmion state (A-phase) is one kind of such novel magnetic phase where spin forms the vortex-like ordering. This phenomena was initially discover in metallic MnSi and later realized in insulating Cu2OSeO3. This unusual magnetic ordering appeared in a finite temperature and magnetic field window. In this present work we are studying the influence of nonmagnetic element substitution on the skyrmion phase of the Cu2OSeO3 system. Polycrystalline (Cu1-xZnx)2OSeO3 ( x = 0, 0.01, 0.02, 0.04, 0.06, 0.08, 0.10, 0.15, 0.20) samples were synthesized using solid state reaction method and characterized by XRD, and magnetic measurements. The crystal structure belongs to the non-centrosymmetric cubic space group P213. Variation of lattice constant with Zn doping follows the Vegard’s law which signifies the fairly successful substitution of Zn in place of Cu up to x≦0.20. The Curie temperature and the value of magnetization decrease with higher Zn doping indicate the ferrimagnetic ordering is gradually suppressed. Moreover, we have notice another magnetic phase for the doping level 0.02<x<0.20, whose magnetic transition also shifted to low temperature for higher Zn doping. The H-T magnetic phase diagrams of all the samples from ac susceptibility by scanning magnetic field (χˈac-H) have been established with increasing Zn doping. The explanations for the observations of doping effects on the A-phase of skyrmion Cu2OSeO3 will be discussed.

論文審定書+i
論文公開授權書+ii
致謝+iii
論文摘要+iv
Abstract+v
目錄+vi
圖目錄+vii
表目錄+viii
第一章：簡介+1
1-1 Skyrmion+1
1-2 Cu2OSeO3簡介+4
1-3 研究動機+8
第二章：樣品製作及實驗量測介紹+10
2-1 (Cu1-xZnx)2OSeO3, x = 0 to 0.20製備方法+10
2-2 X-ray 結構檢測+11
2-3超導量子干涉儀+12
2-3-1 儀器介紹+12
2-3-2 量測方式+16
第三章：實驗結果與討論+18
3-1 X-ray結構檢測結果+18
3-2 磁性量測結果+21
第四章：結論+45
參考文獻+47

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