Dielectric properties of Ba_1-xSr_x(Fe_0.5Ta_0.5)O₃ giant dielectric ceramics

ABSTRACT

The Ba_1-xSr_x(Fe_0.5Ta_0.5)O₃ ceramics were fabricated via a solid-state technique. Effects of Sr-doping on phase formation, densification and dielectric properties were investigated. XRD data revealed that all ceramics had perovskite structure with cubic symmetry. However, single phase was obtained only at x ≤ 0.1. All samples presented high dielectric constant-frequency dispersion with high dielectric constants. Complex impedance analysis indicated that heterogeneous conduction that occurred in the studied ceramics, should be the primary reason for the dielectric constant-frequency dispersion with high dielectric constants. However, the electrode effect was found to dominate for the x = 0.1 ceramic as a result in the very strong dielectric constant-frequency dispersion with very high dielectric constants (ϵ_r ∼ 1.58 × 10⁵ at 310°C).

KEYWORDS:

• Barium strontium iron tantalum
• giant dielectric ceramics
• perovskite structures

Funding

This work was supported by The Thailand Research Fund (TRF, BRG6080002 and IRG5780013), the National Research Council of Thailand, National Research University (NRU) Project under Thailand's Office of the Higher Education Commission, Materials Science Research Center, Chiang Mai University. Department of Physics and Materials Science, Faculty of Science, Graduate School, Science and Technology Research Institute, Chiang Mai University, Thailand is also acknowledged.