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Sign Change of Thermopower at Low Temperatures in Nd0.7 ( Ca,Sr,Ba)0.3 MnO3 |
| ZHOU Sheng-Ming1,2;DONG Qiu-Zhao1;ZHOU Gui-En1,ZHANG Yu-Heng1
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| 1Structure Research Laboratory, University of Science and Technology of China, Hefei 230026
2Department of Physics, Anhui University, Hefei 230039
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| Cite this article: |
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ZHOU Sheng-Ming, DONG Qiu-Zhao, ZHOU Gui-En et al 2000 Chin. Phys. Lett. 17 46-48 |
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Abstract The temperature dependence of thermopower and resistivity for the series of Nd0.7 ( Ca,Sr,Ba)0.3 MnO3with a fixed average A-site cation radius have been measured. Infrared spectra revealed that the size differences between various A-site ions cause large local distortions of MnO6 octahedra. The thermopower is enhanced above metal-insulator transition temperature Tm and is reduced below Tm by increasing amount of A-site cation disorder. The sign change of thermopower induced by A-site cation disorder has been observed at low temperatures. The observed thermopower behaviors have been explained by Mott's formula and the effect of the spin disorder scattering.
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| Keywords:
72.15.Jf
71.38.+i
75.30.Et
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Published: 01 January 2000
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