Synthesis and dc conductivity of Nd2/3TiO2.988

The A-site deficient perovskite Nd2/3TiO3 − δ was synthesized under an H2-CO2 gas mixture. The sample was found to have slight oxygen deficiency of δ∼0.012. The crystal structure was assigned to a double perovskite structure with orthorhombic space group Pmmm, as in the case of La2/3TiO3 − δ. Electrical conductivity measurement has also been performed. The temperature dependence of conductivity shows that electronic transport in Nd2/3TiO2.988 is well described by Emin-Holstein adiabatic small polaron model. The polaron density extracted from the conductivity measurement is ∼1.96 × 1020 cm− 3. This result agrees well with nominal polaron density for Nd2/3TiO2.988, ∼2.1 × 1020cm− 3. We have also derived important quantities for transport in Nd2/3TiO2.988.