Electrical Properties of K₃Li₂Nb₅O₁₅ Ceramics with Substitutions of Ba and Sr

ABSTRACT

The tetragonal tungsten bronze type of K_{6 - x}Ba_xLi_{4 - x}Nb₁₀O₃₀ (KBLN; 0.0 ≤ x ≤ 4.0) and K_{6 - x}Sr_xLi_{4 − x} Nb₁₀O₃₀ (KSLN; 0.3 ≤ x ≤ 0.7) ceramics were synthesized using the solid state reaction method. Lattice parameters, axial ratio (√ 10 · c/a), the Curie temperature (T_C), maximum dielectric constant (κ_max), dielectric diffuseness (γ, C/κ_max) and the degree of ionic disordering were examined as a function of Ba and Sr substitution. The Curie temperature decreased as the respective substitution of Ba and Sr increased. The axial ratio showed a close relationship with the Curie temperature. Correlation between the dielectric diffuseness and ion ordering calculated from the site occupancy was also found.

Keywords:

• Tungsten bronze structure
• KBLN
• KSLN
• ferroelectrics
• diffuse phase transtion

ACKNOWLEDGEMENT

This work was supported by Grant No.R01-2003-000-11606-0 from the Basic Research Program of the Korea Science & Engineering Foundation.