- 學位論文
建構材料量测之同步輻射光束線
Construction of Synchrotron Radiation X-ray Beamlines for Materials Chaterization
摘要
在BL07A光束線設計部份，為了達到能量的範圍在5~23kev、光通量(flux)越高越好、high harmonic waves 反射率在2%以下和能量解析(energy resolution)越低越好的要求，我做了有關於各類型分光儀的比較，以及考慮到面鏡大小對擺放的影響，並模擬出各種材質在不同入射角的反射率，最後選出入射角度為3.5mrad為最佳，就材質而言，準直鏡(Collimating Mirror)一半不鍍，一半鍍上Pt25nm+Rh5nm，聚焦鏡(Focusing Mirror)鍍上Pt25nm+Rh5nm，最後透過shadow模擬軟體模擬出在焦點的光點大小約2.5E-2cm*2.8E-2cm ，能量解析(energy resolution)度從5kev的1.43E-04隨著能量增加而增加，到最高能量23kev時變成2.90E-04，光通量(flux)在7kev到9kev時最大(約7.60E+12)，在23kev時最小(約2.73E+11)。 在X光做樣品分析部分，我們研究的目標是找出不同尺寸的ZrO2以及不同尺寸的ZrO2摻雜不同濃度的Fe、Co、Ni等過渡金屬或其他元素的local structure、晶型和所表現出的物理特性例如磁性、介電常數K值、透光率等等跟尺寸大小的關係，希望從裡面發現新的物理現象，而目前只做到單一尺寸ZrO2和在ZrO2裡摻雜比例為Zr:44.7wt%比Ni5.61wt%的Ni (wt=weight)。結果顯示約3.6nm大小的ZrO2奈米粒子在室溫下是Tetragonal，不同於ZrO2的塊材(bulk)是Monoclinic，而且從EXAFS分析的結果中看到理論上2.38A附近的4個O好像空掉了(oxygen vacancy)，目前還無法知道是受到製程環境的影響還是奈米尺度的影響。ZrO2 doped Ni的樣品在EXAFS分析的結果指出除了2.38A附近的4個O也空掉之外，Ni好像在Zr附近形成NiO或Ni而沒有取代Zr的位置。 目前bulk ZrO2在磁性方面還沒有結論，有一方認為d0 Oxide compounds在室溫下有機會有鐵磁性而且磁性可能是因為O空掉(oxygen vacancy)或摻雜特別雜質而造成O能階分裂所產生的，而另一方則反對這個論點，他們認為 d0 Oxide compounds在室溫下不可能有鐵磁性。在bulk ZrO2的介電常數k值方面，Tetragonal ZrO2的 值約35左右，而O空掉(oxygen vacancy)對介電常數k值的影響是可以被估計的。
並列摘要
In the construction of BL07A beamline, in order to conform to the requests of the energy range from 5 kev to 23kev, the highest flux, the lowest high harmonic waves and the best energy resolution. I have taken all kinds of Monochromators to compared with each other as well as consider the impact of size limit of mirror and the reflectivity in different materials and incident angles. I found the better incident angle is 3.5mrad and the coatings of Collimating Mirror are one half of nothing, a half of Pt25nm+Rh5nm and Pt25nm+Rh5nm for Focusing Mirror. The beam size is 2.5E-2cm*2.8E-2cm . The energy resolution is 1.43E-04 at 5kev with increase to 2.90E-04 at 23kev. The flux is in the highest limit with 7.60E+12 from 7kev to 9kev and in the lowest value with 2.73E+11 at 23 kev. In the analysis of samples with X ray, we want to know the size effect with any properties such as magnetism, K value...etc, the lattice and the local structure of different size ZrO2 and ZrO2 doped Fe、Co、Ni or other atoms. We have done the only one size ZrO2 and the ZrO2 doped Ni with Zr:44.7wt% to Ni5.61wt%. I found that the 3.6 nm ZrO2 is Tetragonal different from the Monoclinic with bulk ZrO2 at room temperature. The EXAFS shows four oxygen vacancy at 2.38A. I am not sure how it happened. ZrO2 doped Ni also shows four oxygen vacancy at 2.38A and Ni or NiO are found around Zr in no substitution of Zr. There is no answer whether bulk ZrO2 is ferromagnetic or not at room temperature at present. One thinks d0 Oxide compounds could be if there is oxygen vacancy or doping which makes energy band of oxygen splitting but the others do not. The k value of tetragonal ZrO2 is 35. The influence of oxygen vacancy could be calculated.