What is it about?
A new in situ high-pressure neutron diffraction technique was developed with a Paris–Edinburgh press employing sintered diamond anvils. The methodology and data correction procedure enabled the reliable measurement of neutron diffraction patterns that are largely free from diamond Bragg peaks. The technique was used to measure the structure of GeO2 glass at pressures up to 17.5 GPa. The results show different densification regimes in the transformation from a tetrahedral to an octahedral glass. A suitable scaling of the density provides the pressure regimes for similar changes in glassy SiO2.
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Why is it important?
The development of neutron diffraction techniques is important because the method provides complementary information to x-ray diffraction on the structure of disordered materials. The new high-pressure method was applied to the prototypical network-forming glass GeO2, providing new insight into the mechanisms of densification that will also apply to other disordered materials such as silica glass.
Perspectives
The new high-pressure method was difficult to develop because of the Bragg peaks that originate from the sintered diamond anvils. The results were rewarding, providing new insight into the behaviour of glassy materials under pressure.
Professor Philip S Salmon
University of Bath
Read the Original
This page is a summary of: Density-driven structural transformations in network forming glasses: a high-pressure neutron diffraction study of GeO 2 glass up to 17.5 GPa , Journal of Physics Condensed Matter, September 2012, Institute of Physics Publishing,
DOI: 10.1088/0953-8984/24/41/415102.
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