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Ti‐Rich Nonstoichiometric BaTiO 3 : II, Analysis of Defect Structure *
Author(s) -
LONG S. A.,
BLUMENTHAL R. N.
Publication year - 1971
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.1151-2916.1971.tb12211.x
Subject(s) - impurity , ionization , limiting , partial pressure , electrical resistivity and conductivity , acceptor , oxygen , conductivity , band gap , range (aeronautics) , materials science , atmospheric temperature range , chemistry , condensed matter physics , thermodynamics , ion , physics , mechanical engineering , organic chemistry , quantum mechanics , engineering , composite material
A defect structure which incorporates singly and doubly ionized nonstoichiometric oxygen vacancies and acceptor states, presumably associated with impurities, was inferred from the agreement between the theoretically derived relationand the experimentally observed O 2 ‐partial‐pressure and temperature dependence of the conductivity. This relation describes the behavior over the entire O 2 pressure and temperature range investigated. A simplified defect model gave good agreement for the limiting case where n> >p but was shown to be in error compared with the more comprehensive relation above. The standard enthalpies of formation for singly and doubly ionized O vacancies in BaTiO 3 , are 4.3 and 5.7 eV, respectively. The difference between these values, 1.4 eV, corresponds to a donor energy level which lies near the middle of the band gap.