Dramatic impact of raw chemicals on the electrical properties of SrTiO3 ceramics

The dielectric loss (tan δ) value of stoichiometric SrTiO3 (ST), prepared using the solid-state reaction method, exhibits a random variation between 0.0006 and 0.01968 at room temperature and a frequency of 1 kHz in the literature. This variability makes it challenging to obtain reliable and reproducible performance for ST-based devices, especially when the underlying reasons are not yet completely understood. This work reports the significant effects of different raw materials, with various forms of TiO2, on the dielectric and electrical properties of ST ceramics. The results show that the purity of SrCO3 and TiO2 ultimately leads to distinct differences in dielectric properties, impedance properties, activation energy across the ST ceramics. Crystal comparison demonstrates that anatase TiO2 is more suitable for dielectric applications. These results provide a reasonable explanation for the large variations in reported ST properties in the literature, which emphasizes the critical importance of selecting suitable reagents in ST-based ceramics. This insight opens up a new avenue for design optimization and highlights the promising potential of ST-based ceramics.