SCIENCE AT THE SHINE DOME canberra 6 - 8 may 2009

New Fellows Seminar

Thursday, 7 May 2009

Professor Raymond Withers FAA
Research School of Chemistry, Australian National University

Ray Withers obtained his PhD in physics from the University of Melbourne followed by post doctoral positions at the University of Toronto and the University of Bristol. He arrived at the Australian National University in 1986 and has been professor of materials chemistry there since 2004. His research interests lie in the synthesis, structural characterisation and crystal chemical understanding of the structures and properties of functional inorganic solid state materials. In particular, he is interested in compositionally and/or displacively flexible crystalline solids whose structures and properties are finely balanced and hence can be fairly easily altered via external influences such as temperature, composition, applied electric and/or magnetic fields or pressure) or that exhibit order which cannot be described using classical crystallographic concepts (such as incommensurately modulated, compositely modulated and quasicrystalline structures as well as many so called random solid solutions).

Local crystal chemical flexibility – structure and function in the crystalline solid state

Structure and function are closely linked in the solid state. Useful materials are very often on the edge of thermodynamic stability and hence able to respond to the application of an applied external signal such as an applied electric and/or magnetic field, or an applied stress. Indeed, it is this very flexibility that gives them their useful properties. Such materials (eg, piezoelectrics, ferroelectrics and pyroelectrics) are ubiquitous in devices all around us, for example mobile phones, sensors and microwave antennas. A detailed understanding of the structures (on all relevant length scales) of such materials is essential for an understanding of their useful physico-chemical properties and of methods to optimise and manipulate them. Electron microscopy, if used appropriately, is a particularly powerful tool for studying structure whether static or dynamic and its relationship to function.