Impact of two-step calcination on microstructure, phase, electronic, and dielectric properties of KCa2Nb3O10 bulk layered perovskite

Jeong Yeon Kim, Jong Chan Lim, Sang il Kim, Seong Mee Hwang, Weon Ho Shin, Heesun Yang, Kyu Hyoung Lee, Hyun Sik Kim

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

The effects of varying calcination temperature, K content, and the number of calcination steps in the dielectric performance of KCa2Nb3O10 synthesized via solid-state reaction are investigated. Adding an extra calcination step at 500°C followed by another calcination at 1100°C suppressed the formation of secondary phases while maximizing the relative density (95%) and the average grain area (2.12 μm2). The first calcination at 500°C ensures the formation of intermediate phases (KNbO3 and Ca2Nb2O7), which are prerequisites for single-phase KCa2Nb3O10 synthesis. A significantly high dielectric constant of 352 at 100k Hz is achieved in the two-step calcined sample despite the low sintering temperature of 1250°C. The highest resistivity of the two-step calcined sample (2 × 108 Ω cm) obtained from complex impedance analysis supports its lowest dielectric loss (0.034 at 100k Hz). When the two-step calcined KCa2Nb3O10 powder is exfoliated, much higher dielectric properties of Ca2Nb3O10 nanosheets are expected.

Original languageEnglish
Pages (from-to)188-196
Number of pages9
JournalJournal of Asian Ceramic Societies
Volume11
Issue number1
DOIs
StatePublished - 2023

Keywords

  • KCaNbO
  • dielectric constant
  • layered perovskite
  • multi-layer ceramic capacitor
  • two-step calcination

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