Structural and Dielectric Properties of CuO, PbO and Bi2O3 Doped SrTiO3 Ceramics

Copper oxide, lead oxide and bismuth oxide each 10% doped separately with 90% SrTiO3 (ST) ceramic powders were processed by solid-state route technique. We reported the effect of Cu+2, Pb+2 and Bi+3 ions on the dielectric response of ST and copper addition established the substantial increase in dielectric constant (εr) than undoped ST from 303K-673K and low loss (tanδ) for good dielectric applications. In case of lead doped ST the strong relaxation dynamics of loss factor was observed at higher temperatures and dielectric constant plots established the curie transition temperature Tc = 653K revealing the structural transformation from cubic to tetragonal phase. But bismuth doped ST contrary to the expectations exhibited the decreasing trend of permittivity form 303K-525K and afterwards showed increasing nature with relaxations. The microstructure was examined by field emission scanning electron microscope (FESEM). Some additional phases SrCu3Ti4O12, PbTi3O7, SrBi3Ti5O18 and TiO2 rutiles were detected by X-ray diffraction technique.