Solid state synthesis and analyses of Sr4(Sr2Ta2)O11 complex perovskite with reduced heat treatment steps

In this work we report the structure, thermal and electrical properties of complex perovskite Sr4(Sr2Ta2)O11 synthesized by solid state reaction route assisted by high energy ball milling. With the help of thermal analysis the required final perovskite phase was obtained through single step calcination process. The XRD patterns of 900 °C calcined samples showed the formation of single phase double perovskite structure. After sintering at 1200 °C for 10 h the crystal structure changed from cubic to tetragonal symmetry due to possible oxygen vacancy ordering. Detailed study of total conductivity using impedance spectroscopy measurements of the sintered pellet showed an increase in conductivity up to 580 °C. However, a reverse effect was observed above 600 °C due to the ion-ion interaction in the disordered lattice, which begins to dominate, leading to a decrease in total conductivity.