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Characterization of Lanthanum‐Doped Barium Titanate Ceramics Using Impedance Spectroscopy
Author(s) -
Morrison Finlay D.,
Sinclair Derek C.,
West Anthony R.
Publication year - 2001
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.1151-2916.2001.tb00694.x
Subject(s) - lanthanum , oxygen , materials science , barium titanate , dielectric spectroscopy , analytical chemistry (journal) , ceramic , argon , electrical resistivity and conductivity , barium , doping , mineralogy , inorganic chemistry , composite material , metallurgy , chemistry , electrode , optoelectronics , electrochemistry , organic chemistry , chromatography , electrical engineering , engineering
The electrical properties of two single‐phase, lanthanum‐doped BaTiO 3 compositions, x = 0.03 and x = 0.20, in Ba 1– x La x Ti 1– x /4 O 3 were investigated by impedance spectroscopy after heat treatment in oxygen, argon, and air at 1350°C. Samples heated in oxygen were electrically insulating, whereas those heated in argon lost oxygen and were semiconducting at room temperature, irrespective of x . Samples heated in air showed intermediate electrical properties and also were electrically inhomogeneous; the two compositions showed different electrical behaviors, and a model for each, based on oxygen nonstoichiometry within the ceramics, is proposed. Oxygen deficiency in samples sintered in air was avoided by heating at 1200°C, instead of 1350°C. Alternatively, oxygen lost from ceramics heated in air at 1350°C was regained by postannealing in oxygen at 1350°C.