Microstructure-property relationships of rare-earth-zinc-oxide varistors

P. Williams, O. L. Krivanek, G. Thomas, M. Yodogawa

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


The microstructure and properties of ZnO varistors containing Ba, Co, and rare-earth-metal oxides, which give values of α [α=d(log I)/d(log V)] as high as 29, are examined. Mean ZnO grain size is 11 μm, and the grains are uniformly doped with Co. The barium and rare earth metals concentrate into 1.5-μm-wide particles embedded in a matrix of ZnO grains. Within the grains and at grain boundaries, the barium and rare-earth-metal concentration is below the detection limit of the energy-dispersive spectrometer technique (about 0.5%). No intergranular films, amorphous or crystalline, are detected, to within 10 Å resolution. These results are shown to be consistent with the grain boundary charge depletion model for the voltage barrier formation and breakdown.

Original languageEnglish (US)
Pages (from-to)3930-3934
Number of pages5
JournalJournal of Applied Physics
Issue number7
StatePublished - 1980
Externally publishedYes

ASJC Scopus subject areas

  • General Physics and Astronomy


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