skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Electrotransport-induced unmixing and decomposition of ternary oxides

Abstract

A general expectation is that in a uniform oxygen activity atmosphere, cation electrotransport induces a ternary or higher oxide, e.g., AB{sub 1+ξ}O{sub 3+δ}, to kinetically unmix unless the electrochemical mobilities of, say, A{sup 2+}and B{sup 4+} cations are identically equal, and eventually to decompose into the component oxides AO and BO{sub 2} once the extent of unmixing exceeds the stability range of its nonmolecularity ξ. It has, however, earlier been reported [Yoo et al., Appl. Phys. Lett. 92, 252103 (2008)] that even a massive cation electrotransport induces BaTiO{sub 3} to neither unmix nor decompose even at a voltage far exceeding the so-called decomposition voltage U{sub d}, a measure of the standard formation free energy of the oxide (|ΔG{sub f}{sup o}| = nFU{sub d}). Here, we report that as expected, NiTiO{sub 3} unmixes at any voltage and even decomposes if the voltage applied exceeds seemingly a threshold value larger than U{sub d}. We demonstrate experimentally that the electrochemical mobilities of Ni{sup 2+} and Ti{sup 4+} should be necessarily unequal for unmixing. Also, we show theoretically that equal cation mobilities appear to be a sufficiency for BaTiO{sub 3} only for a thermodynamic reason.

Authors:
;  [1];  [1];  [2]
  1. Department of Materials Science and Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)
  2. (Germany)
Publication Date:
OSTI Identifier:
22399348
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 12; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BARIUM COMPOUNDS; CARRIER MOBILITY; CATIONS; DECOMPOSITION; ELECTRIC CONDUCTIVITY; ELECTRIC POTENTIAL; ELECTROCHEMISTRY; FORMATION FREE ENERGY; NICKEL IONS; OXYGEN; PHASE STABILITY; TITANATES; TITANIUM IONS

Citation Formats

Chun, Jakyu, Yoo, Han-Ill, E-mail: hiyoo@snu.ac.kr, Martin, Manfred, and Institute of Physical Chemistry, RWTH Aachen University, 52056 Aachen. Electrotransport-induced unmixing and decomposition of ternary oxides. United States: N. p., 2015. Web. doi:10.1063/1.4915626.
Chun, Jakyu, Yoo, Han-Ill, E-mail: hiyoo@snu.ac.kr, Martin, Manfred, & Institute of Physical Chemistry, RWTH Aachen University, 52056 Aachen. Electrotransport-induced unmixing and decomposition of ternary oxides. United States. doi:10.1063/1.4915626.
Chun, Jakyu, Yoo, Han-Ill, E-mail: hiyoo@snu.ac.kr, Martin, Manfred, and Institute of Physical Chemistry, RWTH Aachen University, 52056 Aachen. Sat . "Electrotransport-induced unmixing and decomposition of ternary oxides". United States. doi:10.1063/1.4915626.
@article{osti_22399348,
title = {Electrotransport-induced unmixing and decomposition of ternary oxides},
author = {Chun, Jakyu and Yoo, Han-Ill, E-mail: hiyoo@snu.ac.kr and Martin, Manfred and Institute of Physical Chemistry, RWTH Aachen University, 52056 Aachen},
abstractNote = {A general expectation is that in a uniform oxygen activity atmosphere, cation electrotransport induces a ternary or higher oxide, e.g., AB{sub 1+ξ}O{sub 3+δ}, to kinetically unmix unless the electrochemical mobilities of, say, A{sup 2+}and B{sup 4+} cations are identically equal, and eventually to decompose into the component oxides AO and BO{sub 2} once the extent of unmixing exceeds the stability range of its nonmolecularity ξ. It has, however, earlier been reported [Yoo et al., Appl. Phys. Lett. 92, 252103 (2008)] that even a massive cation electrotransport induces BaTiO{sub 3} to neither unmix nor decompose even at a voltage far exceeding the so-called decomposition voltage U{sub d}, a measure of the standard formation free energy of the oxide (|ΔG{sub f}{sup o}| = nFU{sub d}). Here, we report that as expected, NiTiO{sub 3} unmixes at any voltage and even decomposes if the voltage applied exceeds seemingly a threshold value larger than U{sub d}. We demonstrate experimentally that the electrochemical mobilities of Ni{sup 2+} and Ti{sup 4+} should be necessarily unequal for unmixing. Also, we show theoretically that equal cation mobilities appear to be a sufficiency for BaTiO{sub 3} only for a thermodynamic reason.},
doi = {10.1063/1.4915626},
journal = {Journal of Applied Physics},
number = 12,
volume = 117,
place = {United States},
year = {Sat Mar 28 00:00:00 EDT 2015},
month = {Sat Mar 28 00:00:00 EDT 2015}
}