Dielectric properties of Na_1-xK_xNbO₃ (NKN) (0.160 ≤ x ≤ 0.200) ceramics synthesized by double sintered method

Abstract

In this study, pellet samples of Na_1-xK_xNbO₃ (NKN) (0.160 ≤ x ≤ 0.200) were prepared using the solid- state reaction method with double sintering. Electric conductivity (σ), loss tangent (tan δ), and dielectric constant (ε) were observed for all the prepared compositions from room temperature (RT) to 480 ^oC, at 10, 100, and 1000 KHz. For the prepared compositions (0.160 ≤ x ≤0.200), XRD patterns were observed at room temperature. For the pellet samples (0.160 ≤ x ≤0.200), escaping of Na and K were found minimum for the compositions with x = 0.175. The EDAX confirms ‘p- type’ conductivity in Na_1-xK_xNbO₃ ceramics_. Further, the conductivity was found minimum due to less ‘A- site’ vacancy concentration, near MR region. The electrical conductivity (σ) and dielectric constant (ε) were found minimum for x = 0.175, among the prepared compositions.

Keywords:

• Ceramics
• dielectric constant
• ferroelectrics
• phase transitions