Synthesis and Characterization of Nanocrystalline SrTiO3

The synthesis and densification of fairly dense nanocrystalline SrTiO₃ and its characterization are described in this paper in detail. Significant grain growth was avoided by the application of a two-stage sintering process using hot pressing. High-resolution transmission electron microscopy and electron energy loss spectroscopy characterizations indicate pure material with no detectable chemical inhomogeneities. The electrical measurements indicate the disappearance of bulk contribution to the electrical conduction due to the overlap of depleted space charge layers if the grain size is below 100 nm. Owing to the overlap, the capacitance appears as bulk-like rather than due to space charge polarization. Non-contact sub-millimeter optical spectroscopy measurements reveal strong suppression of the dielectric constant values at low temperature.