Internal barrier layer capacitor, nearest neighbor hopping, and variable range hopping conduction in Ba1−x Sr x TiO3−δ nanoceramics

Soumitra Sulekar (1) , Ji Hyun Kim (1) , Hyuksu Han (2, 3) , Pascal Dufour (2) , Christophe Tenailleau (2) , Juan Claudio Nino (1) , Eloisa Cordoncillo (4) , Hector Beltran-Mir (4) , Sébastien Dupuis (2) , Sophie Guillemet (2)

1 UF - University of Florida [Gainesville]
2 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux
3 Korea Institute of Industrial Technology
4 Universitat Jaume I = Jaume I University

The dielectric properties of the solid solution Ba1−x Sr x TiO3−δ (0 ≤ x ≤ 1) have been investigated. The nanopowders were prepared via a coprecipitation reaction followed by a calcination treatment. Spark plasma sintering allowed to obtain dense nanocrystalline ceramics. Broadband impedance spectroscopy revealed colossal permittivity (ε′ = 105) associated with low losses (tan δ = 0.03) in the most favorable case. The bulk conductivity data was analyzed using Jonscher’s universal dielectric response model. In the Ba-rich compound, conduction process followed variable range hopping conduction model while the Sr-rich BST compound showed the nearest neighbor hopping conduction mechanism associated with displacements of space charges. These two different conduction mechanisms might be able to explain superior temperature–frequency-independent dielectric properties in Sr-rich BST compound compared to Ba-rich BST compound.

Mots clés: Internai barrier layer capacitor (IBLC); Universal dielectric response (UDR)

Domaines: Matériaux

Soumitra Sulekar, Ji Hyun Kim, Hyuksu Han, Pascal Dufour, Christophe Tenailleau, et al.. Internal barrier layer capacitor, nearest neighbor hopping, and variable range hopping conduction in Ba1−x Sr x TiO3−δ nanoceramics. Journal of Materials Science, 2016, 51 (16), pp.7440-7450. ⟨10.1007/s10853-016-0019-0⟩. ⟨hal-02429192⟩