High-pressure neutron study on silica glass at J-PARC high-pressure neutron diffractometer PLANET

Hattori, Takanori   ; Yagafarov, O.*; Katayama, Yoshinori; Chiba, Ayano*; Sano, Asami   ; Inamura, Yasuhiro  ; Otomo, Toshiya*

SiO glass is an amorphous solid consisting of SiO tetrahedra. Each tetrahedra are connected to each other, and forms the many-menbered ring. Thus, the glass has large void space and therefore marked densification is expected under pressure. Actually, the density increases by 20% on compression to 8 GPa, accompanying the change in the intermediate range order. The density goes back to the original one on room-temperature decompression, but the high-density state is maintained once the sample is heated under pressure by structural relaxation (permanent densification). So far, the mechanism has been investigated, but remains to be revealed. To reveal the mechanism, in situ high-pressure diffraction is indispensable. Such data were obtained up to 10 GPa at the high-pressure neutron diffactometer PLANET in the last year, therefore we developed the method to analyze the data this year. By developing the program, we succeeded in obtaining structure factor and confirmed its reliability by comparing with the previous results.