Current limiting by n-type barium titanate ceramics having no positive temperature coefficient in resistance

Journal Article · Fri Jan 01 04:00:00 EST 1993 · Materials Research Bulletin; (United States)

DOI:https://doi.org/10.1016/0025-5408(93)90004-W· OSTI ID:5986650

Kutty, T R.N.; Ravi, V ^[1]

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1. Materials Research Centre, Bangalore (India). Indian Institute of Science

Stable current-limiting characteristics are observed for n-BaTiO[sub 3] ceramics which do not exhibit positive temperature coefficient in resistance (PTCR). These ceramics have been prepared by reannealing the sintered polycrystalline n-BaTiO[sub 3] after painting on the disks with low melting mixtures of PbO+Bi[sub 2]O[sub 3]+B[sub 2]O[sub 3] and thereby modifying the grain boundary layer regions. The power handling capability can be altered by the addition of isovalent lattice substituents as well as the grain boundary layer modifiers such as Al[sub 2]O[sub 3]+SiO[sub 2]+TiO[sub 2] and controlling the donor concentrations in the bulk by regulating the oxygen content in the sintering atmosphere. The current-limiting in semiconducting titanates arises out of the combined influence of joule-heating that modifies the diffuse phase transition and the field effect by way of charge carrier tunneling across the asymmetric barriers at the grain boundary regions.

• OSTI ID: 5986650
• Journal Information: Materials Research Bulletin; (United States), Journal Name: Materials Research Bulletin; (United States) Vol. 28:1; ISSN MRBUAC; ISSN 0025-5408
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
CERAMICS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
FABRICATION
GRAIN BOUNDARIES
MATERIALS
MICROSTRUCTURE
N-TYPE CONDUCTORS
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SEMICONDUCTOR MATERIALS
TITANATES
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS