The structure of MgO-SiO2 glasses at elevated pressure

Area of Science:

• Geophysics
• Materials Science
• Mineral Physics

Background:

• The magnesium silicate system is crucial for understanding planetary formation.
• Neutron diffraction provides insights into the structure of glasses and liquids.

Purpose of the Study:

• To investigate structural changes in magnesium silicate glass under high pressure.
• To develop a method for accurate structural characterization of compressed glass.

Main Methods:

• In situ neutron diffraction at high pressure (up to 8.6 GPa).
• Development of a method for calculating the total structure factor, S(Q).
• Reverse Monte Carlo (RMC) simulations for structural analysis.

Main Results:

• Observed changes in chemical ordering with increasing pressure.
• Increased magnesium-oxygen (Mg-O) coordination number.
• Distortion of the local magnesium ion environment and increased Si-O bond connectivity.

Conclusions:

• High pressure induces significant structural modifications in magnesium silicate glass.
• The findings contribute to understanding the behavior of silicate liquids under planetary conditions.
• The study provides a framework for analyzing structure-dependent properties in related materials.