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Some A{sub 6}B{sub 5}O{sub 18} cation-deficient perovskites in the BaO-La{sub 2}O{sub 3}-TiO{sub 2}-Nb{sub 2}O{sub 5} system

Journal Article · · Journal of Solid State Chemistry
 [1];  [2];  [3];  [3];  [1]
  1. State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070 (China)
  2. State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070 (China) and Institute of Inorganic Chemistry, RWTH Aachen University, 52056 Aachen (Germany)
  3. Institute of Inorganic Chemistry, RWTH Aachen University, 52056 Aachen (Germany)
Some dielectric oxides have been synthesized and characterized in the BaO-La{sub 2}O{sub 3}-TiO{sub 2}-Nb{sub 2}O{sub 5} system. Through Rietveld refinement of X-ray powder diffraction data, Ba{sub 5}LaTi{sub 2}Nb{sub 3}O{sub 18} and Ba{sub 4}La{sub 2}Ti{sub 3}Nb{sub 2}O{sub 18} are identified as the A{sub n}B{sub n-1}O{sub 3n} (n=6) type cation-deficient perovskites with space group R3-bar m and lattice constants a=b=5.7106(1)A, and c=42.0666(5)A for Ba{sub 5}LaTi{sub 2}Nb{sub 3}O{sub 18}; a=b=5.6602(1)A, and c=41.8296(5)A for Ba{sub 4}La{sub 2}Ti{sub 3}Nb{sub 2}O{sub 18}, respectively. Their ceramics exhibit high dielectric constant up to 57 and high quality factors (Qf) up to 21,273GHz. The temperature coefficient of resonant frequency ({tau}f) of these ceramics is decreased with the increase of B-site bond valence.
OSTI ID:
20658180
Journal Information:
Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 11 Vol. 177; ISSN 0022-4596; ISSN JSSCBI
Country of Publication:
United States
Language:
English