Effects of sintering atmosphere (N₂ and O₂) on dielectric properties and electrical conductivity of Na(Nb_1−xTa_x)O₃ ceramics

Abstract

Na(Nb_1−xTa_x)O₃ (NNT, x = 0, 0.05, and 0.10) ceramics were prepared by conventional solid-state reaction method in the oxygen (O₂) and nitrogen (N₂) sintering atmospheres, respectively. The phase structure, surface microstructure, dielectric constant (ε), dielectric loss (tan δ), and frequency dispersion of AC conductivity (σ_ac) of the NNT ceramics have been investigated. The results show that the NNT ceramics are of antiferroelectric orthorhombic phase. The values of ε of the NNT ceramics sintered in N₂ are larger than those sintered in O₂ at all temperatures, and the Curie temperature (T_C) of the NNT ceramics sintered in N₂ or O₂ decreases from about 370 °C to 330 °C as x increases from 0 to 0.10. The electrical conductivity analysis shows that the quasi-static activation energies (E_a) at 1 Hz of the samples sintered in O₂ are larger than in N₂, especially for x = 0. These results are expected to promote the research and applications of the NNT-based systems.

Keywords:

• Sintering atmosphere
• dielectric constant
• AC conductivity
• activation energy
• Na(Nb
• Ta)O₃ ceramics

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work is supported by the National Key R&D Program of China [Nos. 2016YFB0402701, 2016YFA0201103], the National Basic Research Program of China [No. 2015CB654605], National Nature Science Foundation of China [Nos. 51672293, 11475240], the Instrument Developing Project of Chinese Academy of Sciences [No. ZDKYYQ20180004], Chinese Academy of Sciences President’s International Fellowship Initiative [Grant/Award Number: 2017VMA0018 and 2011T2G03].