Oxygen nonstoichlometry and dielectric evolution of BaTiO 3. Part I - Improvement of insulation resistance with reoxidation

  • G. Y. Yang
  • , E. C. Dickey
  • , C. A. Randall
  • , D. E. Barber
  • , P. Pinceloup
  • , M. A. Henderson
  • , R. A. Hill
  • , J. J. Beeson
  • , D. J. Skamser

Research output: Contribution to journalArticlepeer-review

Abstract

Impedance spectroscopy, transmission electron microscopy, and electron energy-loss spectroscopy are used to correlate local electrical properties with the microstructure and microchemistry of BaTiO 3 in Ni-electrode multilayer ceramic capacitors. High densities of linear defects and some grains with structural modulations are observed in BaTiO 3 grains in the as-cofired capacitors. The modulated structure is formed on {111} planes of the BaTiO 3. Both types of structural defects are associated with high concentrations of oxygen vacancies. In particular, the oxygen content in the BaTiO 3 grains that are in direct contact with the internal Ni electrodes is less uniform with a systematic decrease in oxygen content towards the electrode. In the capacitors that are reoxidized in a higher oxygen partial pressure at lower temperature, the BaTiO 3 grains are almost free of linear defects and structural modulations and the oxygen content is homogeneous throughout the BaTiO 3 active layers. A concomitant improvement in the total insulation resistance is observed.

Original languageEnglish (US)
Article number8
Pages (from-to)7492-7499
Number of pages8
JournalJournal of Applied Physics
Volume96
Issue number12
DOIs
StatePublished - Dec 15 2004

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy

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