论文标题
Bi $ _ {2} $ SR $ _ {2} $ CACU $ _ {2} $ o $ $ $ $ _ {8+x} $以及通过Rietveld Refinement研究的竞争间的结合和共结晶阶段的定量阶段分析。
Quantitative phase analysis of Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+x}$ and competing intergrowth and co-crystallising phases via a Rietveld refinement study
论文作者
论文摘要
我们已经使用Rietveld改进技术来确定Bi $ _ {2} $ SR $ _ {2} $ CUO $ _ {6+X} $相位和竞争阶段的共结晶的高温超级导体的共结晶程度bi $ _ {2} $ sr $ _ {2} $ cacu $ _ {2} $ o $ $ _ {8+x} $（bi-2212）。通过使用两种不同的自升压技术生长的BI-2212的单晶制成的BI-2212粉末，即在BI-2212的粉末衍射图上进行完善，即，压力技术（PT）和再生技术（RG）。 Jana和FullProf计划用于改进，两者都取得了一致的结果。 BI和SR Atom的位置在Centrosmmortric Space Group $ BBMB $的平均结构中进行了完善。为了合并BI原子调制和调制向量，在中心对称空间组N $^{BBMB} _ {1 \ bar {1} 1} $（BBMB（0 $γ$ 1））中进行了细化。发现与RG样品相比，调制载体的B*分量随PT样品中超导过渡温度的降低而降低，这表明CUO $ _2 $平面相对于PT样品中的BI-O平面的比对更好。还发现所有样品都表现出强烈的优选方向效应。获得了与首选方向函数相对应的三月散热酶参数的值。我们还计算了Brindley吸收对比因子\ textit {t} $ _ ϕ $以及微吸收对每个样品中存在的相量的影响。融合了所有因素的Rietveld改进，导致了所有样品的特殊值，其拟合参数的优点值为PT样品接地2分钟的最低值2.08。此外，发现与PT晶体相对应的粉末没有共结晶阶段和$ \ sim $ 94 $ \％$ \％$ bi-2212阶段，这表明按压力技术生长的晶体质量非常好，比RG透射技术生长的晶体要好得多。
We have used Rietveld refinement technique to determine the extent of intergrowth of Bi$_{2}$Sr$_{2}$CuO$_{6+x}$ phase and co-crystallization of competing phases in a high temperature superconductor Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+x}$ (Bi-2212). The refinement was done on powder diffractograms obtained on powders of Bi-2212 made by grinding single crystals of Bi-2212 grown using two different self-flux techniques, namely pressure technique (PT) and regrowth technique(RG). JANA and FullPROF programs were used for refinement, both of which gave consistent results. Bi and Sr atom's positions were refined in the average structure of centrosymmetric space group $Bbmb$. To incorporate for Bi atoms modulation and modulation vector, refinement was done in centrosymmetric space group N$^{Bbmb}_{1\bar{1}1}$(Bbmb(0$γ$1)). It was found that the b* component of the modulation vector decreased with a decrease in the superconducting transition temperature in PT sample compared to the RG sample, suggesting a better alignment of the CuO$_2$ planes with respect to Bi-O planes in PT sample. All the samples were also found to exhibit strong preferred orientation effect. Values of March-Dollase parameters corresponding to the preferred orientation function were obtained. We also calculated Brindley absorption contrast factors \textit{t}$_ϕ$ and the effect of micro-absorption on the quantity of phases present in each sample. A Rietveld refinement incorporating all the factors resulted in exceptional values of goodness of fit parameters for all the samples with the lowest value of 2.08 found for the PT sample ground for 2 minutes. Additionally, the powders corresponding to the PT crystals were found to have no co-crystallising phase and $\sim$ 94$\%$ Bi-2212 phase, suggesting that crystals grown by pressure technique are of extremely good quality, much better than those grown by RG flux technique.
