Ferroelectric polaron in layered perovskite ferroelectric thin films

High quality SrBi₂Ta₂O₉ (SBT) ferroelectric thin films were fabricated on platinized silicon substrate by pulsed laser deposition. Electronic transport properties of SBT ferroelectric thin films in temperature range of 10 K to 300 K were studied. The conduction mechanisms in the thin films were analyzed. The results indicate the existence of two conduction mechanisms in SBT ferroelectric thin films. Due to the SBT layered structure, the carrier transport can be divided into two parts: internal transport, which is between the (Bi₂O₂)²⁺ layers; external transport, which is across the (Bi₂O₂)²⁺ layers. Especially, behavior of electric transport of the polaron as an internal transport carrier is first observed in the SBT ferroelectric thin films. Activation energy of the internal transport carriers is E_a-0.0556 eV. The results can be helpful to understanding the low DC leakage in SBT films at room temperature.