| N-type Oxide Thermoelectric Materials Having Spin/Orbital Correlations |
| Tetsuji Okuda |
| Kagoshima University |
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Since the good p-type thermoelectric (TE) property was discovered in Co oxides [1], transition metal oxides have been expected to be next generation TE materials, because of abundant natural resources and being nontoxic, environmental benign, and stable at high temperatures. However, good n-type oxide TE material being a counterpart of Co oxide has not been found yet till now.
In this talk, I will show our attempts to improve the TE properties at room temperature for some candidates of n-type oxide TE materials such as SrTiO3 [2,3] and CaMnO3 [4,5] by element substitutions, together with relative good n-type TE property of Fe-pnictide at low temperatures [6,7]. Based on these results, I will discuss about the effects of the spin/orbital correlations of 3d transition metal ions and the associated local lattice distortions on the TE properties of these oxides.
References:
[1] I. Terasaki, Y. Sasago, and K. Uchinokura, Phys. Rev. B 56, R12685 (1997).
[2] T. Okuda, K. Nakanishi, S. Miyasaka, and Y. Tokura, Phys. Rev. B 63, 113104 (2001).
[3] J. Fukuyado, K. Narikiyo, M. Akaki, H. Kuwahara, and T. Okuda, Phys. Rev. B 85, 075112 (2012).
[4] M. Ohtaki, H. Koga, T. Tokunaga, K. Eguchi, and H. Arai, J. Solid State Chem. 120, 105 (1995).
[5] T. Okuda and Y. Fujii, J. Appl. Phys. 108, 103702 (2010).
[6] L. Pinsard-Gaudart, D. Bérardan, J. Bobroff, and N. Dragoe: Phys. Status Solidi: Rapid Res. Lett. 2, 185 (2008).
[7] T. Okuda, W. Hirata, A. Takemori, S. Suzuki, S. Saijo, S. Miyasaka, and S. Tajima, J. Phys. Soc. Jpn. 80, 044704 (2011).
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| Acknowledgements : This work was partially supported by JSPS KAKENHI Grant No. 25400378. |
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