Order-disorder phase transitions and high-temperature oxide ion conductivity of Er{sub 2+x}Ti{sub 2-x}O{sub 7-{delta}} (x = 0, 0.096)

Journal Article · Thu Apr 12 00:00:00 EDT 2007 · Materials Research Bulletin

DOI:https://doi.org/10.1016/j.materresbull.2006.07.011· OSTI ID:21000624

Shlyakhtina, A V ^[1]; Levchenko, A V ^[2]; Abrantes, J C.C. ^[3]; Bychkov, V Yu ^[1]; Korchak, V N ^[1]; Rassulov, V A ^[4]; Larina, L L ^[5]; Karyagina, O K ^[5]; Shcherbakova, L G ^[1]

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1. Semenov Institute of Chemical Physics, Russian Academy of Sciences, ul. Kosygina 4, Moscow 119991 (Russian Federation)
2. Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Moscow Region 142432 (Russian Federation)
3. UIDM, ESTG, Instituto Politecnico de Viana do Castelo, Apartado 574, 4901-908 Viana do Castelo (Portugal)
4. All-Russia Research Institute of Mineral Resources, Staromonetnyi per. 31, Moscow 119017 (Russian Federation)
5. Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, ul. Kosygina 4, Moscow 119991 (Russian Federation)

The Er{sub 2+x}Ti{sub 2-x}O{sub 7-{delta}} (x = 0.096; 35.5 mol% Er{sub 2}O{sub 3}) solid solution and the stoichiometric pyrochlore-structured compound Er{sub 2}Ti{sub 2}O{sub 7} (x = 0; 33.3 mol% Er{sub 2}O{sub 3}) are characterized by X-ray diffraction (phase analysis and Rietveld method), thermal analysis and optical spectroscopy. Both oxides were synthesized by thermal sintering of co-precipitated powders. The synthesis study was performed in the temperature range 650-1690 deg. C. The amorphous phase exists below 700 deg. C. The crystallization of the ordered pyrochlore phase (P) in the range 800-1000 deg. C is accompanied by oxygen release. The ordered pyrochlore phase (P) exists in the range 1000-1200 deg. C. Heat-treatment at T {>=} 1600 deg. C leads to the formation of an oxide ion-conducting phase with a distorted pyrochlore structure (P2) and an ionic conductivity of about 10{sup -3} S/cm at 740 deg. C. Complex impedance spectra are used to separately assess the bulk and grain-boundary conductivity of the samples. At 700 deg. C and oxygen pressures above 10{sup -10} Pa, the Er{sub 2+x}Ti{sub 2-x}O{sub 7-{delta}} (x = 0, 0.096) samples are purely ionic conductors.

• OSTI ID: 21000624
• Journal Information: Materials Research Bulletin, Vol. 42, Issue 4; Other Information: DOI: 10.1016/j.materresbull.2006.07.011; PII: S0025-5408(06)00299-6; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0025-5408
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AMORPHOUS STATE
CERAMICS
CHEMICAL PREPARATION
CRYSTALLIZATION
ELECTRIC CONDUCTORS
ELECTROCHEMISTRY
ERBIUM OXIDES
GRAIN BOUNDARIES
HEAT TREATMENTS
IMPEDANCE
IONIC CONDUCTIVITY
ORDER-DISORDER TRANSFORMATIONS
PHASE STUDIES
PYROCHLORE
SINTERING
SOLID SOLUTIONS
SPECTROSCOPY
STOICHIOMETRY
THERMAL ANALYSIS
X-RAY DIFFRACTION