Structural Study of Reversible Phase Change Recording Materials by Anomalous Garzing Incidence X-ray Scattering

本研究的目的是利用反常X射线散射（AXS）方法精确分析掠入射条件下相变记录材料（CD-RW）的可逆结构变化。相变记录材料利用了非晶相和晶相之间光学反射率的变化，作为数字信息的存储介质，引起了人们的广泛关注。这些材料已经商业化，并且它们的升级例如容量扩大和高可靠性将在未来越来越多地推进。由于显示出这种增加的趋势，预计结构控制会极大地影响它们的特性。因此，在原子水平上对相变记录材料的结构进行分析，可能是稳定发展这些领域的重要课题之一。利用反常色散效应的AXS方法可能是获得结构信息的有力工具之一。 关于我们 2000年，利用Ge和Br的K吸收边，从AXS测量中估算了Ag-Br-Ge-O非晶态体系的局域结构信息。计算得到的结构参数表明，GeO_4四面体单元可能是该玻璃的结构单元，Ag和Br离子的排列与晶态AgBr相似。从这些结果，有效性的AXS方法表征非晶材料可以确认。在2001年，能量色散掠入射X射线反射测量的有用性和有效性已被证明用于表征多层界面。该方法似乎有望通过使用高能白色X射线辐射并获得高得多的反射强度来降低由于上层吸收而导致的常规角色散方法的难度。从本研究的所有结果来看，将本方法扩展到其他系统将是非常有趣的。少

The purpose of this research is to analyze precisely the reversible structural change in phase change recording materials represented for CD-RW by the anomalous X-ray scattering (AXS) method under the grazing incidence condition. The phase change recording materials, using the variation of optical reflectivity between crystalline and non-crystalline phases, attract much attention as a storaging medium of digital information. These materials have already been commercialized and their upgrading such as capacity enlargement and high reliability will advance in future more and more. As showing this tendency to increase, it is anticipated that the structural control greatly influences their characteristics. Therefore, the structural analysis of phase change recording materials in the atomic level might be one of important subjects for developing steadily these fields. The AXS method by using the anomalous dispersion effect may be one of powerful tools for obtaining the structural informatio … More n in the atomic level.In 2000, the local structural information of amorphous Ag-Br-Ge-O system has been estimated from the AXS measurements using Ge and Br K absorption edges. The resultant structural parameters suggest mat GeO_4 tetrahedral unit is the probable structural entity in this glass and the arrangement of Ag and Br ions is similar to that in crystalline AgBr. From these results, effectiveness of the AXS method for characterizing amorphous materials could be confirmed.In 2001, the usefulness and validity of energy dispersive grazing incidence X-ray reflectometry have been demonstrated for characterizing the multilayer interfaces. The method appears to hold promise in reducing difficulty of conventional angular dispersive method due to absorption with an upper layer by enabling the use of high energy white X-ray radiation and obtaining much higher reflected intensity. Taken from all results in this research, it would be very interesting to extend the present method to other systems. Less