Direct evidence for grain boundary potential barrier breakdown via in situ electron holography

Kevin D. Johnson, Vinayak P Dravid*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

Static and dynamic grain boundary potential barrier effects are directly observed at high spatial resolution for a varistor of model structure and chemistry. Grain boundary mechanisms for nonlinear electrical behavior are investigated for Nb-doped SrTiO3 bicrystals by in situ high-resolution electron holography under applied current coupled with electrical measurements. For the static case, holography reveals a positive grain boundary barrier of about 0.45 V, which is indicative of positive grain boundary charge adjoined by negative space charge regions. Under high applied current, in situ holography records the breakdown of this grain boundary barrier in accord with the macroscopic varistor effect, which is reflected in bulk I-V experiments.

Original languageEnglish (US)
Pages (from-to)428-436
Number of pages9
JournalMicroscopy and Microanalysis
Volume5
Issue number6
DOIs
StatePublished - Jan 1 1999

Keywords

  • Electron holography
  • Grain boundary barriers
  • Niobium-doped strontium titanate
  • Space charge

ASJC Scopus subject areas

  • Instrumentation

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