Interfacial segregation in perovskites. Part 4; Internal boundary layer devices

Journal Article · Wed Oct 31 23:00:00 EST 1990 · Journal of the American Ceramic Society; (United States)

DOI:https://doi.org/10.1111/j.1151-2916.1990.tb06469.x· OSTI ID:5155215

Desu, S B ^[1]; Payne, D A ^[2]

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1. Dept. of Materials Engineering, Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (US)
2. Dept. of Materials Science and Engineering, and Materials Research Lab., Univ. of Illinois at Urbana-Champaign, Urbana, IL (US)

A proposed model for interfacial segregation in perovskites, with induced heterogeneous defect distributions, is extended here to account for the formation of internal boundary layer devices, such as positive temperature coefficient of resistance (PTCR) thermistors and internal boundary layer capacitors (IBLC). Boundary layer effects in doped BaTiO{sub 3} are attributed to factors which contribute to the formation of highly resistive boundary layers by a segregation-induced shift in donor incorporation and/or acceptor segregation, and the inhibiting action of segregated donors on boundary mobility and grain growth. The distribution of space charges, formed by electron transfer from conductive grains to resistive boundary layers, leads to the formation of impedance barriers in the grain-boundary vicinity. Depending on the grain size, and on relative size and spatial distribution of the space charge layer and the resistive layer, a transition from semiconducting properties to insulating properties may take place. This model accounts for the observed PTCR and IBLC phenomena.

• DOE Contract Number: AC02-76ER01198
• OSTI ID: 5155215
• Journal Information: Journal of the American Ceramic Society; (United States), Journal Name: Journal of the American Ceramic Society; (United States) Vol. 73:11; ISSN JACTA; ISSN 0002-7820
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
BOUNDARY LAYERS
CHALCOGENIDES
CRYSTAL STRUCTURE
DOPED MATERIALS
ELECTRICAL PROPERTIES
ELECTRON TRANSFER
GRAIN BOUNDARIES
LAYERS
MATERIALS
MICROSTRUCTURE
OXIDES
OXYGEN COMPOUNDS
PEROVSKITES
PHYSICAL PROPERTIES
SEGREGATION
SEMICONDUCTOR MATERIALS
TITANIUM COMPOUNDS
TITANIUM OXIDES
TRANSITION ELEMENT COMPOUNDS