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SUMMARY:Structural hierarchies and phase transitions in perovskites: group
  theoretical constraints and practical applications - Chris Howard (Univer
 sity of Newcastle\, NSW)
DTSTART:20090223T160000Z
DTEND:20090223T170000Z
UID:TALK15563@talks.cam.ac.uk
CONTACT:Ian Farnan
DESCRIPTION:The application of group theoretical methods to the study of p
 hase transitions has been greatly facilitated by the implementation of the
 se methods in computer programs such as ISOTROPY. Structures arising from 
 the application of any specified distortion (irrep) or combination of dist
 ortions to a given parent structure can be listed\, group-subgroup relatio
 nships established\, and the nature of the transitions that might occur be
 tween the different structures assessed.\n\nThe methods have been applied 
 to establish structural hierarchies for perovskites\, which in turn have p
 roved invaluable in assisting experimental investigations. The methodology
  will be illustrated by reference to diffraction studies of the temperatur
 e-induced phase transitions in SrZrO3\, the discovery of a new high temper
 ature phase in WO3\, and elucidation of the temperature-composition phase 
 diagram for (Ca\,Sr)TiO3. More recent applications will also be presented.
 \n\n[1] H. T. Stokes\, D. M. Hatch\, and B. J. Campbell (2007). ISOTROPY\,
  stokes.byu.edu/isotropy.html.\n[2] C.J. Howard and H.T. Stokes (2005)\, 
 ‘Structures and Phase Transitions in Perovskites – A Group Theoretical
  Approach’\, Acta Cryst. A61\, 93-111.\n[3] M.A. Carpenter\, C.J. Howard
 \, K.S. Knight and Z. Zhang (2006)\, ‘Structural Relationships and a Pha
 se Diagram for (Ca\,Sr)TiO3 Perovskites’\, J.  Phys.: Condens. Matter 18
 \, 10725-10749.\n\n
LOCATION:Harker 2 lecture room\, Department of Earth Sciences\, Downing Si
 te
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