Dresden 2009 – scientific programme
Parts | Days | Selection | Search | Downloads | Help
DF: Fachverband Dielektrische Festkörper
DF 4: Multiferroics, Phase Transitions & Relaxors
DF 4.7: Talk
Monday, March 23, 2009, 12:20–12:40, WIL B321
Single-Crystal X-ray Diffraction Study on Lead Scandium Niobate (PSN) and A-site Doped PSN at High Pressures — •Bernd Maier1, Carsten Paulmann1, Ross Angel2, Jens Engel3, Martin Gospodinov4, Boriana Mihailova1, and Ulrich Bismayer1 — 1Mineralogisch-Petrographisches Institut, Universität Hamburg — 2Crystallography Laboratory, Virginia Tech, Blacksburg, USA — 3Institut für Werkstoffwissenschaften, Technische Universität Dresden — 4Institute of Solid State Physics, Bulgarian Academy of Sciences, Sofia, Bulgaria
High-pressure single crystal X-ray diffraction studies at room temperature on the relaxor ferroelectric lead scandium niobate (PSN) as well as Ba- and Bi-doped PSN are presented. A change in the volume compressibility, broadening of diffraction peaks, suppression of diffuse scattering, and the appearance of (hkl)-reflections (h,k,l = 2n+1) using the Fm3m-cell shows that PSN undergoes a phase transition near 2 GPa which is consistent with the results of M. Somayazulu [1]. For A-site doped PSN, the phase transition occours at around 3.5 GPa. The transition for Bi-doped PSN is better pronounced than that for Ba-doped PSN. The suppression of the diffuse scattering at pressures above the phase transition is associated with a decoupling of A- and B-site cations in the existing polar nanoregions which leads to an enhancement of the ferroic distortion in the PbO-system. The decoupling also allows the B-site cations to shift back from their off-center positions which leads to the appearance of the reflections in the (hkl)-layers (l = 2n+1).
[1] Somayazulu, M. et al., APS Meeting Abstracts (2008)