Regensburg 2010 – scientific programme

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DF: Fachverband Dielektrische Festkörper

DF 16: Phase Transitions

DF 16.2: Talk

Thursday, March 25, 2010, 14:45–15:05, H11

Common characteristics of displacive and relaxor ferroelectrics — •Annette Bussmann-Holder — Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, D-70569 Stuttgart

The long standing classification scheme of ferroelectrics into either relaxor or displacive ones (the phase transition is driven by a soft phonon mode) is shown to be too restrictive since a smooth crossover between them exists which even admits for a coexistence of both phenomena. This crossover and coexistence is a consequence of the varying density of polar nanoregions due to different doping levels of the respective system. The formation of polar nanoregions is attributed here to intrinsic local modes (ILM) in terms of discrete breathers. Consequences for the dynamics, temperature effects and line width broadening are discussed.