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Title: Electrical conduction mechanism in La{sub 3}Ta{sub 0.5}Ga{sub 5.3}Al{sub 0.2}O{sub 14} single crystals

The electrical conduction mechanism in La{sub 3}Ta{sub 0.5}Ga{sub 5.3}Al{sub 0.2}O{sub 14} (LTGA) single crystals was studied by nonstoichiometric defect formation during crystal growth. Since stoichiometric LTGA is not congruent, the single crystal grown from the stoichiometric melt was Ta-poor and Al-rich, where Al atoms were substituted not only in Ga sites but also in Ta sites. The population of the substitutional Al in Ta sites increased with increasing oxygen partial pressure during growth (growth-pO{sub 2}) in the range from 0.01 to 1 atm. Below 600 °C, substitutional Al atoms in Ta sites were ionized to yield holes, and thus the electrical conductivity of the LTGA crystal depended on temperature and the growth-pO{sub 2}. The dependence of the electrical conductivity on the growth-pO{sub 2} decreased as temperature increased. The temperature rise increases ionic conductivity, for which the dominant carriers are oxygen defects formed by the anion Frenkel reaction.
Authors:
;  [1] ;  [2]
  1. Citizen Holdings Co., Ltd., 840, Shimotomi, Tokorozawa, Saitama 359-8511 (Japan)
  2. Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)
Publication Date:
OSTI Identifier:
22266163
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 114; Journal Issue: 22; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANIONS; CRYSTAL DEFECTS; CRYSTAL GROWTH; ELECTRIC CONDUCTIVITY; MONOCRYSTALS; OXYGEN; PARTIAL PRESSURE; STOICHIOMETRY