TY - JOUR
T1 - High-Temperature Electrical Property and Defect Analysis of the Quintuple Perovskite Layered Cuprates Eu2CaBa2Cu2Ti3O14 and LaYCaBa2Cu2+xTi3-xO14-y
AU - Kane, M. H.
AU - Mansourian-Hadavi, N.
AU - Mason, T. O.
AU - Sinkler, W.
AU - Marks, L. D.
AU - Otzschi, K. D.
AU - Ko, D.
AU - Poeppelmeier, K. R.
N1 - Funding Information:
This work was supported by the National Science Foundation (DMR 91-20000) through the Science and Technology Center for Superconductivity and made use of MRL Central Facilities supported by the National Science Foundation, at the Materials Research Center of Northwestern University (Award No. DMR-9120521) One of the authors (K.O.) is partly supported by a research fellowship of the Japan Society for the Promotion of the Science for Young Scientists.
PY - 1999/11/15
Y1 - 1999/11/15
N2 - High-temperature electrical conductivity and thermopower measurements have been performed on undoped Eu2CaBa2Cu2Ti3O14 and doped and undoped LaYCaBa2Cu2+xTi3-xO14. These quintuple perovskites are members of a family of ordered perovskite-type oxides with double Cu-O sheets and have in-plane Cu-O bond lengths comparable to known superconductors. X-ray diffraction data and transmission electron microscopy show clear evidence of layering in both structures. LaYCaBa2Cu2+xTi3-xO14 exhibits a large-small rare earth ordering on the A′/A″ sites, like its quadruple perovskite counterparts. The transport data indicate that these materials behave similarly to the corresponding quadruple perovskites, but have lower carrier concentrations. The La-Y compound exhibits weaker oxygen partial pressure dependencies in the electrical properties, which are suggestive of a decrease in undesirable oxygen intercalation between the CuO2 sheets. Upon doping with copper on titanium sites, (Cu″Ti), a concomitant amount of oxygen vacancies, (V••o), are introduced, as evidenced by TGA and in situ electrical property measurements. Possible defect models are presented and discussed in light of data from TGA, electrical property measurements, and quantitative high-resolution TEM.
AB - High-temperature electrical conductivity and thermopower measurements have been performed on undoped Eu2CaBa2Cu2Ti3O14 and doped and undoped LaYCaBa2Cu2+xTi3-xO14. These quintuple perovskites are members of a family of ordered perovskite-type oxides with double Cu-O sheets and have in-plane Cu-O bond lengths comparable to known superconductors. X-ray diffraction data and transmission electron microscopy show clear evidence of layering in both structures. LaYCaBa2Cu2+xTi3-xO14 exhibits a large-small rare earth ordering on the A′/A″ sites, like its quadruple perovskite counterparts. The transport data indicate that these materials behave similarly to the corresponding quadruple perovskites, but have lower carrier concentrations. The La-Y compound exhibits weaker oxygen partial pressure dependencies in the electrical properties, which are suggestive of a decrease in undesirable oxygen intercalation between the CuO2 sheets. Upon doping with copper on titanium sites, (Cu″Ti), a concomitant amount of oxygen vacancies, (V••o), are introduced, as evidenced by TGA and in situ electrical property measurements. Possible defect models are presented and discussed in light of data from TGA, electrical property measurements, and quantitative high-resolution TEM.
KW - Cuprates
KW - Electrical conductivity
KW - Electron microscopy
KW - Point defects
KW - Thermopower
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U2 - 10.1006/jssc.1999.8190
DO - 10.1006/jssc.1999.8190
M3 - Article
AN - SCOPUS:0002508051
VL - 148
SP - 3
EP - 15
JO - Journal of Solid State Chemistry
JF - Journal of Solid State Chemistry
SN - 0022-4596
IS - 1
ER -