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High‐Temperature Defect Structure of Acceptor‐Doped Strontium Titanate
Author(s) -
EROR N. G.,
BALACHANDRAN U.
Publication year - 1982
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.1151-2916.1982.tb10508.x
Subject(s) - acceptor , strontium titanate , conductivity , doping , impurity , analytical chemistry (journal) , materials science , crystallite , electrical resistivity and conductivity , oxygen , activation energy , chemistry , nanotechnology , thin film , condensed matter physics , metallurgy , physics , optoelectronics , organic chemistry , chromatography , engineering , electrical engineering
The defect structure of acceptor‐doped (Fe, Al, Cr) polycrystalline strontium titanate was investigated by measuring the equilibrium electrical conductivity as a function of oxygen activity (10 −21 ≤a o2 ≤1) and temperature (85°C≤ T ≤ 1050°C). The electrical conductivity was n type with ∼−1/4 dependence on a 02 for a 02 <10 −10 . For a 02 >10 −8 , the observed data for Fe‐ or Al‐doped samples were proportional to ∼1/4.5 power of a 02 . In this region for Cr‐doped samples, the value of m in.σp αa 02 +1/m varies from ∼4.80 to ∼9.00 as the concentration of Cr is increased from 460 to 10 000 ppm. The onset of p ‐type conductivity depends on the amount. of acceptor impurity added to the sample. The absolute values of the conductivity in the acceptor‐doped samples were lower in the n‐type region than those for undoped SrTiO 3 . The conductivity minima shift toward lower oxygen activity with increasing acceptor concentration. For the entire oxygen activity rangae used in this study, the defect structure of SrTiO 3 is dominated by the added acceptor impurities.