Bi2+x-zSr2-x+zCuOy (x=0-0.1;z=0-0.1)製備、結構與特性研究

Preparation, structure and properties of Bi2+x-zSr2-x+zCuOy (x=0-0.1;z=0-0.1)compounds

吳致賢(Chih-Hsien Wu)

指導教授 ： 高惠春

淡江大學/理學院/化學學系碩士班/碩士(2005年)

https://doi.org/10.6846/TKU.2005.00750

摘要

本實驗以固態法製備了三系列正交晶系的Bi2+x-zSr2-x+zCuOy單相樣品，取代量為0 ≦ x, z ≦0.10。掃描式電子顯微鏡(SEM)觀察發現樣品多屬層狀結構。EDS分析發現樣品中Bi元素會有0.6 ~ 4.2% 揮發的情況出現。Bi2-zSr2+zCuOy與Bi2Sr2-xCuOy系列樣品的電洞濃度隨取代量增加而增加，有電洞摻雜的效應；反之，Bi2+xSr2CuOy系列樣品則有電洞充填效應。三個系列樣品在正常態時皆呈金屬性；低溫時，會轉變成超導態，Tc(onset) 均隨取代量增加而下降。未取代樣品(Bi2Sr2CuOy)具有最高的Tc(onset)，其值為7.9 K，電洞濃度為0.237。XANES光譜分析所得的相對電洞濃度與碘間接滴定法所得結果變化一致。

關鍵字

電洞濃度 ； 摻雜 ； 超導性 ； Bi2+x-zSr2-x+zCuOy ； XANES

並列摘要

In this research, sigle phase orthorhombic Bi2+x-zSr2-x+zCuOy compounds with 0 ≦ x, z ≦ 0.10 were prepared by a solid state reaction method. Laminar structure is observed for all the samples under SEM. EDS analysis show that Bi is volatile, the depletion amount is in the range of 0.6 ~ 4.2%. Hole concentration of the Bi2-zSr2+zCuOy and Bi2Sr2-xCuOy series samples increases with increasing x (or z), showing a hole doping effect. In contrary, Bi2+xSr2CuOy series samples show a hole filling effect. Bi2+x-zSr2-x+zCuOy series samples are metallic in normal state and they are superconductors at lower temperature. Tc(onset) decreases with increasing x (or z). Bi2Sr2CuOy has the highest Tc at 7.9 K with an optimal hole concentration of 0.237. Hole concentration obtained from XANES and iodometric titration agrees well in the Bi2+x-zSr2-x+zCuOy compounds.

並列關鍵字

hole concentration ； doping ； superconductivity ； XANES ； Bi2+x-zSr2-x+zCuOy

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