Modulated Electron Density of Inorganic Compounds using SR

本研究的目的是利用同步辐射来确定功能无机材料的调制结构和电子密度。到目前为止，使用单晶衍射技术进行精确分析受到了消光效应的影响，这种消光效应往往会降低运动学理论所期望的入射强度。从实用的角度来看，本研究似乎成功地解决了这一问题，使用了尺寸约为10微米的小晶体，并使用了高通量的同步辐射源。得到的结果是：(A)确定了Ta_2O_5-WO_3固溶体中的非公度调制结构，(B)确定了Mg_6SO_2(OH)_2的结构。(C)SmFeO_3，YFeO_3，HoFeO_3，C型稀土倍半氧化物，Y_2BaCuO_5超导化合物，LaOCl层状结构，LiNbO_3和LiTaO_3光电材料，铁铝辉石的合成矿物，含钴橄榄石，(D)Nb_2Zr_&lt；X-2&GT；O_2&lt；2X-1&GT；在x=8的情况下，(E)使用雪崩光电二极管等开发快速X射线计数器。所有这些研究都是在日本高能物理实验室(KEK)的光子工厂进行的，在大多数情况下，使用14A光束线的水平式四圆衍射仪。首席研究员现在记住一个想法，即该项目由小组成员成功地实施，其结果在很大程度上为参与材料科学和结晶学的科学界做出了贡献。

The present study has been carried out with the objective to determine modulated structures and electron densities of functional inorganic materials using synchrotron radiations. The precise analysis using the single crystal diffraction technique has so far been suffered from the extinction effect which often reduces the incident intensity expected from the kinematical theory. The present study seems to have succeeded in eliminating the problem from practical point of view, by the use of small crystal of about 10 micrometer in size and by the use of the synchrotron source with high flux. The results obtained are (a) determination of incommensurately modulated structure in the Ta_2O_5-WO_3, solid solution, (b) determination of the structure of Mg_6SO_2(OH)_<14> needle-shaped tiny crystals which can not be grown more than 100 micron in length and several micron in width, (c) electron density measurements on SmFeO_3, YFeO_3, HoFeO_3, C-type rare-earth sesquioxides, Y_2BaCuO_5 superconduction-related compound, LaOCl layred-type structure, LiNbO_3 and LiTaO_3 optoelectronic materials, a synthetic mineral of ferrian aluminian diopside, cobalt-containing olivine, (d) determination of compositely modulated structure of Nb_2Zr_<X-2>O_<2X-1> with x=8, (e) development of a fast X-ray counter using the avalanche-photo-diodes, etc. All these studies were done at the Photon Factory, High-Energy Physics Laboratory (KEK), Japan, in most cases, using the horizontal-type four-circle diffractometer at the beamline 14A.The head investigator now bears in mind a thought that this project has successfully conducted by the group members and the results have contributed to the scientific communities involved in the materials science and crystallography to a great extent.