Structural transformations and anomalous viscosity in the BO melt under high pressure

Brazhkin, V. V.*; Farnan, I.*; Funakoshi, Kenichi*; Kanzaki, Masami*; Katayama, Yoshinori; Lyapin, A. G.*; Saito, Hiroyuki

Physical Review Letters, 105(11), p.115701_1 - 115701_4, 2010/09

https://doi.org/10.1103/PhysRevLett.105.115701

Liquid BO represents an archetypical oxide melt with the cation coordination number 3 and unusual structural units - planar boroxol rings. It features super-high viscosity at melting temperature. The results of the X-ray diffraction study and viscosity measurements of the BO liquid under high pressure up to 8 GPa are presented. Additionally, the NMR study of BO glasses quenched from the melt at different pressures has been carried out. The number of the boroxol rings in the melt rapidly decreases with pressure. The viscosity of the BO melt along the melting curve drops by 4 orders of magnitude as the pressure increases up to 5.5 GPa and remains unchanged on further pressure increase.