Pair Distribution Function Studies of Inorganic Materials Under Extreme Conditions

Authors: Tim Lucas (University of Birmingham)
Co-authored by industrial partner: No

Type: Thesis

State: Published (Approved)
Published: November 2013
Diamond Proposal Number(s): 794 , 6855 , 7496 , 8080

Open Access Open Access

Abstract: This study concentrates on pair distribution function (PDF) analysis of various related systems under extreme conditions using variable temperatures and pressures. The local structure of BaTiO3 (BTO) was investigated using x-rays (xPDF) between 0 and 8.78 GPa and x-rays and neutrons (nPDF) between 100 and 500K. Evidence is presented that indicates that the “Comes model” of Ti disorder is too simplistic to describe the local structure of BTO at variable temperature but results from the high pressure xPDF study are inconclusive due to the inability to observe the very weak first Ti-O peak. The ambient structure of related Ba1−xBixTi1−xYbxO3 was also investigated using both nPDF and xPDF between x = 0 and 0.15, with PDFs indicating significant local disorder present on both A and B sites. Cubic ZrMo2O7 undergoes pressure induced amorphisation at ~0.7 GPa and this was investigated up to 11.02 GPa using xPDF which showed an increase in Mo coordination with pressure but no significant change around Zr. Iron undergoes a bcc-hcp phase transition between 10 and 20 GPa and xPDF was used to investigate this phase transition and the local structure of the hcp phase up to 50.07 GPa, but texture in the sample at high pressures hindered analysis.

Journal Keywords: Qd Chemistry

Subject Areas: Chemistry, Materials

Instruments: I15-Extreme Conditions

Other Facilities: APS

Added On: 21/04/2015 17:53

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