title: Transformation in intermediate-range structure of vitreous silica under high pressure and temperature.
abstract: The pressure dependence of the structure factor for vitreous silica was measured up to 8.3 GPa at 500 °C by means of an in situ x-ray diffraction method. The position of the first sharp diffraction peak (FSDP) moved to a higher momentum transfer as the pressure increased. It moved rapidly between 3.3 and 5.8 GPa, and then the slope of the FSDP position as a function of pressure decreased. The pressure dependence of the position is the same as that for a sample heated to 500 °C after room-temperature compression. On decompression at 500 °C, the position of the FSDP showed hysteresis. The pressure dependence of the FSDP position suggests that the permanent densification of vitreous silica is realized due to preservation of the intermediate-range structure stabilized at high pressure and temperature.
authors.affiliation: Materials and Life Science Division, J-PARC Center, Japan Atomic Energy Agency, 2-4 Shirakata-Shirane, Tokai, Naka, Ibaraki 319-1195, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Inamura
authors.forename: Y
authors.initials: Y
authors.lastname: Katayama
authors.forename: W
authors.initials: W
authors.lastname: Utsumi