Pressure-dependent Raman modes near the cubic-tetragonal transition in strontium titanate

KİRACI A., YURTSEVEN H. H.

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, cilt.101, sa.3, ss.1344-1355, 2018 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 101 Sayı: 3
  • Basım Tarihi: 2018
  • Doi Numarası: 10.1111/jace.15279
  • Dergi Adı: JOURNAL OF THE AMERICAN CERAMIC SOCIETY
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.1344-1355
  • Anahtar Kelimeler: dielectric relaxation, phase transformations, Raman spectroscopy, strontium titanate, PHASE-TRANSITION, LANDAU THEORY, TEMPERATURE, SRTIO3, PEROVSKITES, BOUNDARIES, SCATTERING, PHONONS
  • Orta Doğu Teknik Üniversitesi Adresli: Evet

Özet

The pressure dependence of the Raman frequency shifts of various Raman modes is calculated at room temperature using the volume data from the literature for the cubic-tetragonal transition in SrTiO3. The isothermal mode Gruneisen parameters of those Raman modes are obtained, which decrease with increasing pressure for this molecular crystal. Calculated Raman frequencies are then used to predict the damping constant and the inverse relaxation time of those Raman modes as a function of pressure by means of the pseudospin-phonon (PS) coupled model and the energy fluctuation (EF) model to describe the cubic-tetragonal transition in SrTiO3. Also, the values of the activation energy are extracted for the Raman modes studied using both models (PS and EF). Our predicted damping constant and the inverse relaxation time for the Raman modes, can be compared with the experimental measurements close to the cubic-tetragonal transition in SrTiO3.