The Intermediate Phase of Quartz. I

抄録

The intermediate phase (IP) between the α and β phases of quartz was studied by means of X-ray diffraction topography and a fine-beam Laue photography. It is an incommensurate phase characterized by six modulation vectors which are nearly parallel to ±b_i directions but rotated either positively or negatively around the c-axis. The regions with the opposite rotation make a domain structure. The temperature dependence of the modulation vectors (q) was precisely determined. The “microtwins” model for IP is criticized by elementary diffraction theory and our observations; mainly (g, q) dependence of the satellite intensities where g is the reflection vector. A “configuration wave” model is more plausible. In addition, the principles and practical procedures in applying the Laue method to the quantitative study of satellite reflections are presented.