Microstructure and dielectric properties of compositionally graded Ba1-xSrxTiO3 multilayer tunable capacitors

Hyun Ju Choi, Jong Un Woo, Hyun Gyu Hwang, Dae Su Kim, Mohan Sanghadasa, Sahn Nahm

Research output: Contribution to journalArticlepeer-review

Abstract

Li2O/B2O3-added Ba1-xSrxTiO3 (B1-xSxT) ceramics, where 0.2 ≤ x ≤ 0.35, were well densified at 920 °C with pure perovskite structure. The dielectric constant, tunability, and figure of merit (FOM) of B1-xSxT ceramics increased with x because of the decreasing Curie temperature (TC). The specimen with x = 0.35, whose TC was close to room temperature, exhibited a large tunability of 27.4 % and FOM of 110 at 10 kV/cm. A compositionally graded multilayer (CGML), which was sintered at 920 °C, was fabricated using B1-xSxT thick films to produce a temperature-stable tunable capacitor, and it evinced a dense microstructure and a continuous interface between the B1-xSxT thick film and the Ag electrode. This CGML capacitor showed a large tunability (51 %) and FOM (150) at 20 kV/cm. It also exhibited stable tunability (17–28 % at 10 kV/cm) at temperatures between 30–90 °C. Therefore, the B1-xSxT CGML capacitor is a suitable candidate for temperature-stable tunable capacitors.

Original languageEnglish
Pages (from-to)2559-2567
Number of pages9
JournalJournal of the European Ceramic Society
Volume41
Issue number4
DOIs
Publication statusPublished - 2021 Apr

Keywords

  • Ba1-xSrxTiO3
  • Graded multilayer ceramics
  • Low temperature co-fired ceramic
  • Tape casting
  • Temperature-stable tunable device

ASJC Scopus subject areas

  • Ceramics and Composites
  • Materials Chemistry

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