Colossal permittivity and low losses in Ba1–xSrxTiO3–δ reduced nanoceramics

Sébastien Dupuis (1) , Soumitra Sulekar (2) , Ji Hyun Kim (2) , Hyuksu Han (1, 3) , Pascal Dufour (1) , Christophe Tenailleau (1) , Juan Claudio Nino (2) , Sophie Guillemet-Fritsch (1)

1 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux
2 UF|MSE - Department of Materials Science and Engineering [Gainesville]
3 Korea Institute of Industrial Technology

The oxalate route offers a controlled approach to synthesize pure Ba1–xSrxTiO3 (BST) (0 ≤ x ≤ 1) nanoparticles (ϕ ≈ 150 nm in diameter). Reduced BST dense nanoceramics were obtained by spark plasma sintering (SPS) and then annealed for a short time to reach colossal permittivity ( = 105) with low dielectric losses (tan δ = 0.03) at 1 kHz and 300 K. The effects of Ba–Sr substitution on structural, microstructural and electrical properties were analyzed. Comprehensive analysis of the electrical properties indicates that polaron hopping, mediated by Ti3+ ions and oxygen vacancies is the main contributing mechanism to colossal permittivity in Ba-rich BST compounds. Substitution of Ba by Sr reduced the contribution of polaron hopping and led to a decrease of real and imaginary parts of permittivity, while preserving interfacial polarization and yielding better temperature stability. The lowest temperature coefficient of capacitance, or TCC (variation of capacitance between 310 K and 450 K) value, i.e., 44 ppm K−1, is obtained for SrTiO3.

Mots clés: Barium strontium titanate; Colossal permittivity; Spark plasma sintering; Nanoceramic; Dielectric properties

Domaines: Matériaux

Sébastien Dupuis, Soumitra Sulekar, Ji Hyun Kim, Hyuksu Han, Pascal Dufour, et al.. Colossal permittivity and low losses in Ba1–xSrxTiO3–δ reduced nanoceramics. Journal of the European Ceramic Society, 2016, 36 (3), pp.567-575. ⟨10.1016/j.jeurceramsoc.2015.10.017⟩. ⟨hal-02134637⟩