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Semiconducting Molybdenum Pyrochlores for high Temperature Applications

Published online by Cambridge University Press:  10 February 2011

V. Ponnambalam  and
U. V. Varadaraju
V. Ponnambalam
Affiliation:
Materials Science Research Centre, Indian Institute of Technology Madras 600 036. INDIA.
U. V. Varadaraju
Affiliation:
Materials Science Research Centre, Indian Institute of Technology Madras 600 036. INDIA.
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Abstract

The solid solutions (Y1-xYbx)2Mo2O7 were prepared and the systematic changes in the electrical resistivity (ρ=l/σ), thermopower (S) and power factor (S2σ) have been studied in the temperature range 300–900 K. The lattice parameters ‘a’ and ‘c’ are smaller for higher Yb3+ content phases due to smaller Yb3+ radius and a small tetragonality is observed for all the phases. Semiconducting behaviour is seen for all compositions with systematic increase in activation energy with increasing Yb content. All compositions show negative thermopower indicating electrons are the majority charge carriers in the temperature range of measurements. The calculated power factor values S2σ increase with increasing temperature in the low temperature region and a maximum power factor of ∼0.76×10−7 Wcm−1K−2 is observed at 650K.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 512: Symposium F – Wide Bandgap Semiconductors for High Power, High Frequency , 1998 , 249
Copyright
Copyright © Materials Research Society 1998

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References

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