solid state and materials chemistry

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Our research is directed towards understanding structure-property relationships in metal oxides, and in particular understanding how small charges in composition can have significant impact of chemical on physical properties. Our major methodology is powder diffraction, using X-rays (in-house and synchrotron) neutron and when desperate electrons. These studies are supplemented by X-ray and electron spectroscopy and magnetic measurements.

Project 1

Hosts for inorganic wastes – from dentists to fukushima
The disaster at the Fukushima Dai-ichi nuclear plant has again highlighted the need to develop selective and stable hosts for metal ions, be they nuclear or heavy metal wastes. This work will look at two approaches to the problem. Firstly how good are synthetic mimics of natural hosts? This will focus on preparing and characterising chemically doped apatites – the natural mineral component of bone and teeth. The second approach explores the need for flexibility in the host and in this work we will look at samples near a pyrochlore-fluorite transition.

Project 2

Non-integer oxidation states – what controls the electrons?
Modern electronics are built around metal oxides; from disc drives, to capacitors and batteries. An important property of transition metals incorporated in many devices is their variable oxidation state, a property that also allows complex oxides such as Sr_1-xNa_xRuO₃ to be prepared (a mixed Ru^4+/5+ oxide). In more complex oxides such as Sr_1-xCe_xMnO₃ both the Ce and Mn have variable oxidation states (Ce^3+/4+ - Mn^4+/3+) and this project seeks to establish why this is so. A second project in this area is looking at the competition between anion vacancies and oxidation as appreciable to high temperature fuel cells.

Project 3

Crystallographic phase transitions
Our ability to tune chemical composition through the formation of solid solutions should allow us to also tune the structure. However despite our best intentions anomalies persist and we simply do not have a sufficient body of information to predict phase transitions. In this project we focus on the preparation of perovskite-type materials that exhibit desirable properties (ferroelectrics, magnetism etc) and study how there structures evolve as we change their environment (temperature, pressure).

 

For further information, please contact:

Professor Brendan Kennedy

Room 458

School of Chemistry

Eastern Avenue

University of Sydney NSW 2006

Phone: +61 2 9351 2742

Email: brendan.kennedy@sydney.edu.au