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Title: Effects of rare earth ionic doping on microstructures and electrical properties of CaCu{sub 3}Ti{sub 4}O{sub 12} ceramics

Graphical abstract: The dielectric constant decreases monotonically with reduced RE doping ion radius and is more frequency independent compared with that of pure CCTO sample. - Highlights: • The mean grain sizes decrease monotonically with reduced RE doping ionic radius. • Doping gives rise to the monotonic decrease of ϵ{sub r} with reduced RE ionic radius. • The nonlinear coefficient and breakdown field increase with RE ionic doping. • α of all the samples is associated with the potential barrier width rather than Φ{sub b}. - Abstract: Ca{sub 1–x}R{sub x}Cu{sub 3}Ti{sub 4}O{sub 12}(R = La, Nd, Eu, Gd, Er; x = 0 and 0.005) ceramics were prepared by the conventional solid-state method. The influences of rare earth (RE) ion doping on the microstructure, dielectric and electrical properties of CaCu{sub 3}Ti{sub 4}O{sub 12} (CCTO) ceramics were investigated systematically. Single-phase formation is confirmed by XRD analyses. The mean grain size decreases monotonically with reduced RE ion radius. The EDS results reveal that RE ionic doping reduces Cu-rich phase segregation at the grain boundaries (GBs). Doping gives rise to the monotonic decrease of dielectric constant with reduced RE ionic radius but significantly improves stability with frequency. The lower dielectric loss of doped samplesmore » is obtained due to the increase of GB resistance. In addition, the nonlinear coefficient and breakdown field increase with RE ionic doping. Both the fine grains and the enhancement of potential barrier at GBs are responsible for the improvement of the nonlinear current–voltage properties in doped CCTO samples.« less
Authors:
 [1] ;  [2] ;  [3] ; ; ;  [3] ;  [1]
  1. School of Materials Science and Engineering, Xi'an University of Technology, Xi'an 710048 (China)
  2. (China)
  3. Department of Technology and Physics, Zhengzhou University of Light Industry, Zhengzhou 450002 (China)
Publication Date:
OSTI Identifier:
22475808
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Research Bulletin; Journal Volume: 66; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; BREAKDOWN; CALCIUM COMPOUNDS; CERAMICS; COMPARATIVE EVALUATIONS; COPPER COMPOUNDS; CURRENTS; DIELECTRIC MATERIALS; DOPED MATERIALS; GRAIN BOUNDARIES; GRAIN SIZE; PERMITTIVITY; RARE EARTH ADDITIONS; RHENIUM ADDITIONS; SEGREGATION; SOLIDS; STABILITY; TITANATES; X-RAY DIFFRACTION