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Electrical Properties of Gadolinium–Europium Zirconate Ceramics
Author(s) -
Xia XiaoLiang,
Ouyang JiaHu,
Liu ZhanGuo
Publication year - 2010
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.1551-2916.2009.03505.x
Subject(s) - europium , pyrochlore , materials science , activation energy , electrical resistivity and conductivity , arrhenius equation , analytical chemistry (journal) , zirconate , solid solution , ceramic , conductivity , raman spectroscopy , mineralogy , chemistry , luminescence , metallurgy , titanate , physics , optoelectronics , organic chemistry , engineering , chromatography , optics , electrical engineering , phase (matter)
(Gd 1− x Eu x ) 2 Zr 2 O 7 (0≤ x ≤1.0) ceramics are prepared via a solid‐state reaction process at 1973 K for 10 h in air. (Gd 1− x Eu x ) 2 Zr 2 O 7 (0.2≤ x ≤1.0) ceramics exhibit an ordered pyrochlore‐type structure; however, Gd 2 Zr 2 O 7 has a disordered defect fluorite‐type structure. Raman spectroscopy analysis indicates that the degree of structural ordering increases with the increase of Eu content. The electrical properties of (Gd 1− x Eu x ) 2 Zr 2 O 7 ceramics are investigated using complex impedance spectroscopy over a frequency range of 0.1 Hz to 20 MHz from 623 to 923 K. Electrical conductivity obeys the Arrhenius equation. Both the activation energy and the preexponential factor for grain conductivity decrease with increasing europium content from Gd 2 Zr 2 O 7 ( x =0) to Eu 2 Zr 2 O 7 ( x =1.0). The measured electrical conductivity of (Gd 1− x Eu x ) 2 Zr 2 O 7 ceramics increases with increasing Eu content and temperature. Electrical conductivity of the pyrochlore‐type materials is higher than that of the defect fluorite‐type material in (Gd 1− x Eu x ) 2 Zr 2 O 7 solid solution systems. The electrical conductivity of (Gd 0.4 Eu 0.6 ) 2 Zr 2 O 7 is almost independent of oxygen partial pressure from 1.0 × 10 −4 to 1.0 atm. The high ionic transference number of (Gd 0.4 Eu 0.6 ) 2 Zr 2 O 7 ceramic at different temperatures proves that conduction is purely ionic with negligible electronic contribution.