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Protonic Conduction in Acceptor‐Doped Cubic Rare‐Earth Sesquioxides
Author(s) -
Norby Truls,
Dyrlie Oddvar,
Kofstad Per
Publication year - 1992
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.1151-2916.1992.tb05556.x
Subject(s) - yttrium , acceptor , proton , conductivity , doping , ion , inorganic chemistry , analytical chemistry (journal) , lanthanide , chemistry , materials science , oxide , condensed matter physics , physics , optoelectronics , organic chemistry , chromatography , quantum mechanics
Using ac conductivity and the concentration cell emf method, conductivity contributions from protons, native ions, and electrons have been measured as a function of temperature (560° to 1156°C) in wet oxygen/air for the cubic systems Y 2 O 3 + 1 mol% MgO, Sm 2 O 3 + 1 mol% CaO, Gd 2 O 3 + 1 mol% CaO, and YYbO 3 + 5 mol% CaO. All exhibit significant proton conductivities as well as native‐ion and electronic conductivities at all temperatures. In wet atmospheres and reduced temperatures, the oxides dissolve protons to compensate for the acceptor doping, at the expense of native positive defects. This dissolution of protons seems to be relatively more favorable in oxides of smaller rare‐earth cations (e.g., Y 3+ and Yb 3+ ). On the other hand, larger cations (e.g., Sm 3+ and Gd 3+ ) give higher proton mobilities. As compared to oxides of the true lanthanides with similar cationic radii, yttrium‐containing oxides have lower proton mobilities.