Phase transitions, dielectric properties, and vibrational study of stannates perovskites Sr1−xErxSnO3−δ

• Substitution Sr/Er in the alkaline earth cage modifies the thermally induced disorder.
• Two phase transitions have been observed by DSC.
• The dielectric constant increases with erbium substitution.
• Dielectric loss increases exponentially with temperature.
• The conductivity contribution is mainly due to hopping process.

A polycrystalline stannates perovskites Sr1−xErxSnO3−δ (x = 0.00, 0.01 and 0.03) were synthesized by sol–gel method and their vibrational properties were investigated using Raman scattering. The substitution of Er in the Sr site, results in a slight change of the position of the Raman spectrum bands. The differential scanning calorimetry (DSC) shows two phase transitions at 532 K and 634 K for Sr0.99Er0.01SnO3−δ. The dielectric behavior of each solid solution (x = 0.01 and x = 0.03) has been studied as a function of temperature and frequency and has confirmed the observed phase transitions. The diffuseness of the phase transitions of these materials enhances with the increasing of erbium content. The dielectric constant showed a strong increase near the phase transitions temperature which value depends with frequency. This phenomenon is usually observed in relaxor materials. The conduction and the dielectric relaxation are attributed to hopping of electrons among Sn2+ and Sn4+ ions.

The diffuseness of the phase transition of the Sr1−xErxSnO3−δ enhances with the increasing of erbium content. These compounds were found to undergo phase transitions with increasing temperature.Figure optionsDownload as PowerPoint slide