Modulated Electron Density of Inorganic Compounds using SR

本研究的目的是利用同步辐射确定功能无机材料的调制结构和电子密度。迄今为止，单晶衍射技术的精确分析一直受到消光效应的影响，消光效应往往降低了运动学理论所期望的入射强度。本研究通过使用10微米大小的小晶体和高通量的同步加速器源，从实用的角度来看，似乎已经成功地消除了这个问题。结果有：(a)测定了Ta_2O_5-WO_3固溶体中的非相应调制结构；(b)测定了Mg_6SO_2(OH)_<14>针状微小晶体的结构，这些晶体的生长长度不能超过100微米，宽度不能超过几微米；(c)测定了SmFeO_3， YFeO_3, HoFeO_3， c型稀土倍半氧化物，Y_2BaCuO_5超导相关化合物，LaOCl层状结构。LiNbO_3和LiTaO_3光电材料，铁铝双辉石合成矿物，含钴橄榄石，(d) x=8时Nb_2Zr_< x -2>O_<2X-1>复合调制结构的测定，(e)雪崩光电二极管快速x射线计数器的研制等。所有这些研究都是在日本高能物理实验室（KEK）的光子工厂完成的，在大多数情况下，使用水平型四圆衍射仪在光束线14A处完成的。首席研究员现在记住了一个想法，这个项目已经由小组成员成功地进行了，结果在很大程度上为材料科学和晶体学领域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.