高圧下での単結晶ー単結晶転移の誘起と高圧相の結晶学的性質の研究

结果表明，压力升高速率是诱导单晶向单晶转变的重要因素之一。在最有利于上述相变的速率下，相变过程中晶体内部结构的改变是有目的的。由于原位观察相变过程在技术上存在困难，因此中断相变过程，用碘化钾显微镜观察回收试样在常压下的表面和断裂面。显微镜观察表明，试样内部和外部的断口结构不同。前者是透明的，相对可裂解的。然而，后一部分是不透明的，完全丧失了可劈裂性，表明这部分是从B2（高压相）恢复的。因此，这一结果表明，相分离是从外部向内部向心进行的。为了获得有关相变机理的更详细的信息，必须对相变过程进行原位观察。为此，建立了金刚石顶锤压力精密控制系统。根据用新装置得到的初步结果，用显微镜观察证实了上述相变过程。

It was found that the pressure-increasing rate is one of the important fac-tors so as to induce the single-crystal to single-crystal transformation. At the most favorable rate for the above-mentioned phase transformation the obser-vation of the internal structure of the crystal was intended in the course of the transformation. As the in situ observation of the process of the phase transformation is technically difficutl, the transformation was interrupted and the surface and the fracture plane of the retrieved specimen to the ambient pressure was observed by means of the microscope for potassium iodide. Accord-ing to the microscope observations the structure of the fracture plane was dif-ferent in the inner part and the outer of the specimen. The former was transparent and relatively cleavable. The latter part, however, was opaque and the cleavableness was lost at all, indicating that this part was retrieved from B2, the high pressure phase. This result, therefore, suggests that the phase transfomation proceeds from the outer part to the inner part centripetally. In order to obtain more detailed information concerning the mechanism of the phase transformation the in situ observation of the process of the phase transforma-tion is indispensable. For the achievement of this purpose the precise pres-sure-controlling system for the diamond anvil was built. According to the pres-liminary result obtained by the use of the new apparatus the above- mentioned process of the phase transformation was confirmed with the miscroscope observa-tion.