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Chemical Diffusivity of BaTiO 3−δ : IV, Acceptor‐Doped Case
Author(s) -
Song ChangRock,
Yoo HanIll
Publication year - 2000
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.1151-2916.2000.tb01273.x
Subject(s) - thermal diffusivity , stoichiometry , doping , diffusion , chemical composition , materials science , analytical chemistry (journal) , acceptor , oxygen , partial pressure , conductivity , mineralogy , thermodynamics , chemistry , condensed matter physics , physics , optoelectronics , organic chemistry , chromatography
The chemical diffusivity of 1.8 mol% aluminum‐doped BaTiO 3−δ was measured on single‐crystal specimens, as a function of ambient oxygen partial pressure, in the range 10 −18 atm ≤ P O2 ≤ 1 atm and at temperatures of 800°≤ T ≤ 1100°C, via a conductivity‐relaxation technique. As in the polycrystalline, undoped BaTiO 3−δ described in Part II of this work, the chemical diffusivity exhibited a maximum, of thermodynamic origin, approximately at the stoichiometric composition (δ= 0). The measured diffusivity was analyzed, based on the defect structure proposed and Wagner's classic theory of chemical diffusion, and the mobilities of the electrons and holes, as well as all of the relevant defect‐equilibrium constants, then were evaluated with no prior assumptions. The evaluated parameters were compared with those for the undoped BaTiO 3−δ .