Nouvelle méthode de synthèse et propriétés de ferrite spinelle pour enregistrement magnétooptique réinscriptible

Abstract
Cobalt ferrite spinels films have been synthesized by oxidizing at different temperatures of a metallic alloy film CoFe₂. This metallic film is deposited on glass substrates by sputtering of a Fe target covered by Co platelets. X ray diffraction data and electron microprobe analysis show that the spinel phase CoFe₂O₄begins to form at 300 °C and crystallizes at higher temperatures. No preferential orientation was observed on glass substrates. Magnetic and magneto-optic properties (Faraday rotation (FR)) are a function of the oxidizing temperature T_ox and particularly at 632.8 nm, FR are strongly related to the distribution of the Co²⁺ ions in the different sites of the spinel structure. Films prepared at T_ox < 600 °C present properties close to those of bulk CoFe₂O₄. The high FR of the films indicate that this method could be used to synthesize Co ferrite spinel derived compounds as MO recording media.