%0 Journal Article
%T Optical investigations of La0.7Ca0.3-xKxMnO3 (x = 0.00, 0.05 and 0.10) probed by spectroscopic ellipsometry
%A N. Sdiri
%A A. Boukhachem
%A E. Dhahri
%J Ceramics-Silik¨¢ty
%D 2012
%I Academy of Sciences of the Czech Republic
%X Using spectroscopic ellipsometry, we have studied the optical properties of doped manganites at the paramagnetic state in polycrystalline La0.7Ca0.3-xKxMnO3 samples for (x = 0.00, 0.05 and 0.10) in the energy range of 3.2-5.5 eV at room temperature. The surface morphology of the samples was obtained by using atomic force microscopy (AFM). Refractive indices, extinction coefficients, the transmission ellipsometric parameters ¦· and ¦¤ are investigated at different wavelengths. The study of the optical conductivity ¦Ò reveals that optical behaviour and the activated transport in the paramagnetic state of these materials are consistent with Jahn-Teller small polaron. In addition, the spectrum of the complex dielectric constant ¦Å reveals peaks for all samples, the results may be explained by the presence of space charges from the strongly dipole-allowed O(2p) Mn(3d) transition.
%K K doped manganites
%K Spectroscopic ellipsometry
%K Complex index
%K Dispersion
%K Phase transition
%U http://www.ceramics-silikaty.cz/2012/pdf/2012_02_95.pdf