Thermal Decomposition of Some Substituted Barium Titanyl Oxalates and Its Effect on the Semiconducting Properties of the Doped Materials |
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| Authors: | PATRICK K GALLAGHER FRANK SCHREY |
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| Affiliation: | Bell Telephone Laboratories, Incorporated, Murray Hill, New Jersey |
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| Abstract: | Thermal analysis has been performed on BaTiO(C2O4)2.4H2O, Ba0.6Sr0.4TiO(C2O4)2.4H2O, Sr(TiO(C2O4)2.4H2O, Ba0.9Pb0.1TiO(C2O4)2.4H2O, and BaTi0.9Zr0.1O(C2O4)2.4H2O. It was observed that the strontium compound decomposes differently than the others. Previous investigators have proposed conflicting mechanisms for the pyrolysis of the barium salt and these results are discussed in comparison with this work. The electrical resistivity and temperature coefficient of fired lanthanum-doped materials were found to vary with the calcination temperature. Maximum conductivity was observed in samples calcined at 900°C whereas maximum positive temperature coefficient was observed for materials calcined at 1050°C. Particle sizes of the calcined material were compared with grain sizes in the fired pieces and correlated with the electrical properties. A cursory examination was made on the effects of fabrication pressure, 1.25 to 15 tsi, on the electrical conductivity. Both the conductivity and positive temperature coefficient were found to increase with decreasing fabrication pressure. |
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