Infrared optical properties of SrBi₂Ta₂O₉ ferroelectric thin films

Infrared optical constants of strontium bismuth tantalate (SBT) ferroelectric thin films have been derived from infrared spectroscopic ellipsometric measurements (2.5-12.5 μm). By fitting the experimental pseudodielectric constants 〈∈₁〉 and 〈∈₂〉 with a three-phase model (Air/SBT/Pt), the optical constants and thickness of the films have been obtained, and an intrinsic vibrational frequency of the films at 802 cm^-1 has also been acquired. The possible contribution to the vibrational frequency has been discussed.