.An Ellipsometric study of Manganese Oxide films". In situ characterization of the deposition and electroreduction of MnO2.

M.HERNÁNDEZ UBEDA; M.A PEREZ; H. T. MISHIMA; H.M.VILLULLAS; J. O. ZERBINO; M.LOPEZ TEIJELO; B.A. LOPEZ

JOURNAL OF THE ELECTROCHEMICAL SOCIETY

The Electrochemical Society

Lugar: Penmyton. New Jersey. USA; Año: 2005 vol. 152 p. 37 - 41

0013-4651

The electrodeposition of manganese oxide films onto a platinum substrate was investigated by means of in situ ellipsometry. In the thickness range from 0 to 150 nm, the anodic oxide behaves as an isotropic single layer with optical constants that are independentof thickness. Deviations at higher thickness are explained in terms of anisotropic properties of the film. The electroreduction of thin films ~up to ca. 150 nm! in an alkaline electrolyte leads to a decrease in both the refractive index and the extinction coefficient and is accompanied by a thickness increase of ca. 10%. The Mn~IV to Mn~III conversion takes place from the oxide/electrolyteinterface inwards.