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Defect Structure of Flash‐Sintered Strontium Titanate
Author(s) -
Karakuscu Aylin,
Cologna Marco,
Yarotski Dmitry,
Won Jonghan,
Francis John S. C.,
Raj Rishi,
Uberuaga Blas P.
Publication year - 2012
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2012.05240.x
Subject(s) - strontium titanate , sintering , materials science , ceramic , flash (photography) , transmission electron microscopy , mineralogy , grain size , conductivity , analytical chemistry (journal) , composite material , nanotechnology , optics , thin film , chemistry , physics , chromatography
Flash sintering of strontium titanate ( SrTiO 3 ) is studied at different applied fields to understand its effect on density and grain growth. In particular, the defect structure is investigated by optical and structural analysis. SrTiO 3 exhibited a trend in densification opposite that of ionically or electronically conductive ceramics: as the applied voltage decreased, the density increased. Abnormal grain growth in conventionally sintered SrTiO 3 is arrested by flash sintering. Interestingly, undoped SrTiO 3 behaved differently than undoped Al 2 O 3 , which did not exhibit any signs of flash sintering. Previous attempts at flash sintering could only be achieved in MgO ‐doped Al 2 O 3 . We believe that non‐stoichiometric Ruddlesden‐Popper phases in SrTiO 3 , as indicated by ultrafast optical spectroscopy, X ‐ray diffraction, conductivity measurements, and transmission electron microscopy, assist flash sintering by increasing local conductivity through enhanced defect content.