Award Date

5-1-2012

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Physics and Astronomy

First Committee Member

Andrew Cornelius

Second Committee Member

Ravhi Kumar

Third Committee Member

Michael Pravica

Fourth Committee Member

Changfeng Chen

Fifth Committee Member

Clemens Heske

Number of Pages

53

Abstract

Three intermetallic compounds, AuX2 (X = Al, Ga, In), were synthesized by arc-melting proper stoichiometric ratios of high purity Au, Al, Ga, and In. They were found to be single-phase in the CaF2 type Fm3m crystalline structure. Interest in these particular intermetallic materials is due to intriguing pressure-induced behavior such as electronic topological transitions (ETTs), and structural phase transitions as well as their use in a variety of practical applications such as a solar spectral absorber and in electronic circuitry. In this study, the high-pressure structure of these materials was studied using high resolution synchrotron x-ray diffraction (XRD) at the Advanced Photon Source at Argonne National Laboratory. Pressure induced structural transitions were observed below 20 GPa in all the samples and the equation of state (EOS) was determined for the Fm3m phase. Our experiments show that compressibility of these compounds vary greatly, where AuIn2 is the most compressible and AuAl2 is the least compressible. Effect of hydrostaticity on the structural phase transition and the phase transition sequence are discussed.

Keywords

Aluminum; Diamond Anvil Cell; Gallium; Gold compounds; High-Pressure; High pressure physics; Indium; Intermetallic compounds; X-Ray Diffraction

Disciplines

Condensed Matter Physics

Language

English


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