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Ruthenium Doped Gadolinium Titanate: Effects of a Variable Valent Acceptor on Ionic and Electronic Conduction

Published online by Cambridge University Press:  25 February 2011

M.A. Spears
Affiliation:
Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
H.L. Tuller
Affiliation:
Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Abstract

We have investigated ruthenium doped gadolinium titanate, Gd2(RuxTi1-x)2O7-δ with 0 ≤ x ≤ 0.2, to determine the role of variable valent Ru in influencing the defect structure and transport properties of the pyrochlore host. We have developed a defect chemical model to interpret electrical conductivity, thermoelectric power, and thermogravimetry data. We have found that Ru acts as an acceptor compensated in large part by oxygen vacancies, resulting in enhanced ionic conduction at low values of x. For larger values (x ≈ 0.05), electronic conductivity predominates which we attribute to electron migration by hopping through a Ru-derived defect band.

Type
Research Article
Copyright
Copyright © Materials Research Society 1993

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