High-temperature phase transitions in SrBi_2Ta_2O_9 film: a study by THz spectroscopy

F. Kadlec; S. Kamba; P. Kuzel; C. Kadlec; J. Kroupa; J. Petzelt

doi:10.1088/0953-8984/16/37/012

High-temperature phase transitions in SrBi_2Ta_2O_9 film: a study by THz spectroscopy

Materials Science 2009-11-10 v1 Disordered Systems and Neural Networks

Authors: F. Kadlec , S. Kamba , P. Kuzel , C. Kadlec , J. Kroupa , J. Petzelt

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Abstract

Time-domain THz transmission experiment was performed on a $\rm SrBi_2Ta_2O_9$ film deposited on sapphire substrate. Temperatures between 300 and 923 K were investigated and complex permittivity spectra of the film were determined. The lowest frequency optic phonon near 28 cm $^{-1}$ reveals a slow monotonic decrease in frequency on heating with no significant anomaly near the phase transitions. We show that the dielectric anomaly near the ferroelectric phase transition can be explained by slowing down of a relaxational mode, observed in the THz spectra. A second harmonic generation signal observed in a single crystal confirms a loss of center of symmetry in the ferroelectric phase and a presence of polar clusters in the intermediate ferroelastic phase.

Keywords

THz spectroscopy phase transition dielectric anomaly relaxational mode ferroelectric phase second harmonic generation

Cite

@article{arxiv.cond-mat/0406705,
  title  = {High-temperature phase transitions in SrBi_2Ta_2O_9 film: a study by THz spectroscopy},
  author = {F. Kadlec and S. Kamba and P. Kuzel and C. Kadlec and J. Kroupa and J. Petzelt},
  journal= {arXiv preprint arXiv:cond-mat/0406705},
  year   = {2009}
}

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subm. to J. Phys.: Condens. Matter

High-temperature phase transitions in SrBi_2Ta_2O_9 film: a study by THz spectroscopy

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