Properties of the low-frequency phonon spectra of ferroelectric barium titanate-based heterostructures

Abstract

Polarized Raman spectra of the epitaxial Ba0.5Sr0.5TiO3 film, bi-color BaTiO3/Ba0.5Sr0.5TiO3 superlattice and tri-color BaTiO3/Ba0.5Sr0.5TiO3/SrTiO3 superlattice were studied in a broad temperature range of 80-700 K. Based on the temperature dependence of the polar modes we determined the phase transitions temperatures in the studied heterostructures. In the sub-THz frequency range of the ( ) spectra, we revealed the coexistence of the Debye-type central peak and soft mode in bi-color BaTiO3/Ba0.5Sr0.5TiO3 superlattice. ARTICLE HISTORY

Crystal Structure and the Spectral Response of the Ba‐Doped SrTiO3 Incipient Ferroelectrics

“…Vibrational spectroscopy methods were used to study the dynamics of phase transitions in various Ba‐doped SrTiO 3 samples prepared in different forms, such as, single crystals and ceramics [ 15,16 ] and films and superlattices on different substrates. [ 17–21 ] It was shown that the soft mode, which is a characteristic of displacive structural phase transitions, is active only in the ferroelectric phase. The soft‐mode behavior allows to determine the Curie temperature ( T C ).…”