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Effects of K doping and annealing on the grain size and giant dielectric constant of K x Ti 0.02 Ni 0.98– x O ceramics
Author(s) -
Kumar Jana Pradip,
Sarkar Sudipta,
Chaudhuri B. K.
Publication year - 2007
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200622553
Subject(s) - grain size , materials science , dielectric , permittivity , non blocking i/o , sintering , doping , annealing (glass) , grain boundary , analytical chemistry (journal) , ceramic , atmospheric temperature range , mineralogy , condensed matter physics , composite material , microstructure , thermodynamics , chemistry , optoelectronics , physics , biochemistry , chromatography , catalysis
Monovalent ion (MOI) doping effect on the grain size and giant dielectric constant ( ϵ ′ ∼ 10 4 ) of lead free environment friendly NiO‐based K x Ti 0.02 Ni 0.98– x O (KTNO, x = 0.04, 0.25, and 0.30) type ceramics have been investigated. Increasing K concentration (MOI) enhances the grain size along with the increase of ϵ ′ values. The dielectric constant of KTNO also increases with increase of the sintering time and temperature (within the range of our measurement) due to enhancement of crystalline size. The giant ϵ ′ value and the leakage current in KTNO show weak field dependent behavior. Estimated temperature coefficient of permittivity (TCP) of KTNO is very low (less than 6%). All these properties meet the requirements of the ceramics used in X7R EIA specification. High ϵ ′ in KTNO is attributed to the boundary layer mechanism. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)