Dielectric and ferroelectric properties of Nb-doped Ba_0.7Ca_0.3TiO₃ ceramics

Abstract

(Ba_0.7Ca_0.3)_1-x/2Ti_1-xNb_xO₃ ceramics where x = 0, 0.01, 0.02 and 0.03 were prepared employing a solid state sintering technique. The site vacancies produced by donor doping affected significantly the dielectric behavior of doped ceramics. Upon increasing the Nb content, the phase transition became much more diffuse due to structural heterogeneity. The transformation temperature from ferroelectric to paraelectric phase was found to decrease in correlation with decreasing tetragonality. Depending on the Nb content, the normal ferroelectric and relaxor-like behaviors of dielectric and ferroelectric properties were resulted from donor-doping induced site vacancies. Based on these results, Ba_0.7Ca_0.3TiO₃ properties may be tunable by Nb dopant and could be an attractive material for high-dielectric response devices.

KEYWORDS:

• Barium calcium titanate
• ferroelectric properties
• perovskites
• dielectric properties

Funding

This research was funded by King Mongkut’s University of Technology North Bangkok. Contract no. KMUTNB-KNOW-61-004. A. Watcharapasorn would like to acknowledge partial funding support on instrumental characterization from the Research Center of Excellence in Physics and Astronomy, Chiang Mai University.