Visualization Method of Ionic Conductivity

无机材料的高温结构测定无论在基础科学上还是在应用上都越来越重要。高分辨中子粉末衍射是这类研究的有力工具。我们一直在KENS脉冲中子装置上开发高分辨率飞行时间(TOF)中子粉末衍射仪(NPD)。利用高分辨率TOF-NPD获得了高质量的结晶学数据。我们成功地利用TOF-NPD进行了高温原位测量。此外，将最大熵方法(MEM)成功地应用于TOF-NPD数据(TOF/MEM)，并用MEM可视化了离子的平均分布。除了平均结构外，离子导体中可移动离子的局域结构对于理解离子导电性的机理也很重要。由TOF中子衍射数据得到的结构因子S(Q)，得到了对分布函数和径向分布函数。

High temperature structural determination of inorganic materials is more and more important in both basic science and application point of view. High resolution neutron powder diffraction is a powerful tool in such studies. We have been developing high resolution Time-of-Flight (TOF) neutron powder diffractometers (NPD) at the pulsed neutron facility KENS. With using high resolution TOF-NPD, high quality crystallographic data are obtained. We have succeeded in high temperature in situ measurement using TOF-NPD. In addition, Maximum Entropy Method (MEM) is successfully applied to TOF-NPD data (TOF/MEM), and average distribution of ions are visualized by MEM. In addition to average structures, local structures of mobile ions in ionic conductors are also important to understand the mechanism of the ionic conductivity. We have obtained the pair distribution function (PDF) and radial distribution function (RDF) from the structure factor S(Q) obtained from TOF neutron diffraction data.