Coherent X-ray diffraction investigation of twinned microcrystals
Coherent X-ray diffraction investigation of twinned microcrystals
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DOI：
10.1107/s0909049510039774
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发表时间：
2010-11-01
影响因子：
2.5
通讯作者：
Robinson, Ian K.
中科院分区：
文献类型：
--
作者：
Aranda, Miguel A. G.;Berenguer, Felisa;Robinson, Ian K.
用相干X射线衍射研究了假半面体孪晶锰氧化物微晶。分析的成分为Pr（5/8）Ca（3/8）MnO（3）和La（0.275）Pr（0.35）Ca（3/8）MnO（3）。通过温和加热将制备的松散粉末热附着到玻璃（和石英）毛细管壁，以确保数据收集期间的位置稳定性。许多衍射数据集被记录下来，其中一些数据被分离，正如主要观察到的孪晶定律所预期的那样：围绕[101]旋转180度。由于衍射数据的高分辨率性质，以非常高的精度测量峰分裂，分辨率（delta d/d）优于2.0 x 10-4。此外，当这些微晶被相干地照射时，结构因子的不同结晶相引起散斑图案形式的干涉。三维斑点布拉格峰强度分布已被测量提供有关的微晶体内的孪晶畴的信息。目前正在进行研究，以扭转测量的模式。成功的相位恢复将允许映射出在物理性质中起关键作用的孪晶畴和孪晶边界。
Coherent X-ray diffraction has been used to study pseudo-merohedrally twinned manganite microcrystals. The analyzed compositions were Pr(5/8)Ca(3/8)MnO(3) and La(0.275)Pr(0.35)Ca(3/8)MnO(3). The prepared loose powder was thermally attached to glass (and quartz) capillary walls by gentle heating to ensure positional stability during data collection. Many diffraction data sets were recorded and some of them were split as expected from the main observed twin law: 180 degrees rotation around [101]. The peak splitting was measured with very high precision owing to the high-resolution nature of the diffraction data, with a resolution (delta d/d) better than 2.0 x 10-4. Furthermore, when these microcrystals are illuminated coherently, the different crystallographic phases of the structure factors induce interference in the form of a speckle pattern. The three-dimensional speckled Bragg peak intensity distribution has been measured providing information about the twin domains within the microcrystals. Research is ongoing to invert the measured patterns. Successful phase retrieval will allow mapping out the twin domains and twin boundaries which play a key role in the physical properties.