| Autor: |
Braun, A., Richter, J., Harvey, A. S., Infortuna, A., Frei, A., Pomjakushina, E., Mun, Bongjin S., Holtappels, P., Vogt, U., Conder, K., Gauckler, L. J., Graule, T. |
| Rok vydání: |
2011 |
| Předmět: |
|
| Zdroj: |
Applied Physics Letters 93, 262103, 2008 |
| Druh dokumentu: |
Working Paper |
| DOI: |
10.1063/1.3049614 |
| Popis: |
Electric conductivity and structural details of the hole-doped polaron conductor La0.9Sr0.1FeO3 (LSF10) are reported. The conductivity of a single crystal shows an exponential increase with temperature with a maxi-mum of 100 S/cm at 700 K and with activation energy of about 375 meV, and a decrease for higher temperatures that follows a power law. The exponential increase of the electric conductivity for 300 K {\leg} T {\leg} 700 is accompanied by a shift of spectral weight in the photoemission valence band towards the Fermi level, indicative of a strong electron-phonon interaction. The subsequent decrease of the conductivity for T > 700 K is accompanied by a reversible phase transformation from orthorhombic to rhombohedral symmetry. The decreasing conductivity for T > 700 K is likely due to the reduction of the iron due to oxygen loss causing a decreasing hole concentration, as evidenced by a substantial chemical shift in the Fe K-shell x-ray absorption spectra. Two additional fine structures in the conductivity data at 357 K, this is, a small temperature reversible jump in the conductivity, and at 573 K, a slight reversible increase of the polaron activation energy, are correlated with an exceptionally strong decrease in spectral valence band intensity near the Fermi level, and with the onset of a corresponding structural transition. |
| Databáze: |
arXiv |
| Externí odkaz: |
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