A Comparative Analysis of BaTiO₃/(Ba,Sr)TiO₃ and BaTiO₃/(Ba,Sr)TiO₃/SrTiO₃ Artificial Superlattices via Raman Spectroscopy

BaTiO₃/Ba₅₀Sr₅₀TiO₃ and BaTiO₃/Ba₅₀Sr₅₀TiO₃/SrTiO₃ superlattices are characterized via Raman spectroscopy. Special attention is paid to a comprehensive analysis of their polarized Raman spectra, especially, within a soft mode (E(1TO)) range. The shift of E(1TO) soft mode is found to be more pronounced for BaTiO₃/Ba₅₀Sr₅₀TiO₃/SrTiO₃ sample than for BaTiO₃/Ba₅₀Sr₅₀TiO₃, presumably owing to stronger 2D compression of BT layers and abruptly increased temperature of transition from ferroelectric to paraelectric phase.

Keywords
BaTiO₃/Ba₅₀Sr₅₀TiO₃; BaTiO₃/Ba₅₀Sr₅₀TiO₃/SrTiO₃ ferroelectric superlattices; soft mode; Raman spectroscopy; strain