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Contribution à l'étude de la conductivité optique du système Pr(1-x)Ca(x)MnO(3)

Abstract : This work is a contribution to the study of low energy excitations in manganites Pr(1-x)Ca(x)MnO3 (0 ≤ x ≤ 1) by reflectivity measurements between 0.01 and 2.2 eV in function of temperature from 4 to 300 K. The properties of these strongly correlated electron systems are governed by competitive interactions which induce a rich and complex phase diagram.
We explain quantitatively the shape and the evolution of the optical conductivity spectra deduced from the reflectivity, by a minimal model constituted by a polaronic excitation and an interband one which are both related to the Jahn – Teller effect. In the FI and AFI-A phases, we link the evolution of the JT excitation spectral weight by a double exchange model. In the charge ordered compounds, we notice under TCO an increase of the optical transitions energies that we explain by a progressive strengthening of the electron – phonon coupling.
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https://tel.archives-ouvertes.fr/tel-00011295
Contributor : Rodolphe Sopracase <>
Submitted on : Wednesday, January 4, 2006 - 2:32:09 PM
Last modification on : Tuesday, July 9, 2019 - 1:24:46 AM
Long-term archiving on: : Saturday, April 3, 2010 - 7:14:27 PM

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  • HAL Id : tel-00011295, version 1

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Rodolphe Sopracase. Contribution à l'étude de la conductivité optique du système Pr(1-x)Ca(x)MnO(3). Matière Condensée [cond-mat]. Université François Rabelais - Tours, 2005. Français. ⟨tel-00011295⟩

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