J. Phys. IV France 07 (1997) C1-261-C1-262
Valence States of Copper and Cation Distribution in Submicron Copper Ferrite Spinels CuxFe3-xO4(0≤x≤1)E. Kester1, B. Gillot1, P. Perriat1, C. Villette2, Ph. Tailhades2 and A. Rousset2
1 Laboratoire de Recherche sur la Réactivité des Solides, UMR 5613, Faculté des Sciences Mirande, BP. 138, 21004 Dijon cedex, France
2 Laboratoire de Chimie des Matériaux Inorganiques, URA 1311 du CNRS, Université Paul Sabatier, 118 route de Narbonne, 31062 Toulouse cedex, France
Valence States studies of copper and iron ions and their cation distribution on both octahedral (B) and tetrahedral (A) sites on the spinel structure of submicron copper-substituted magnetites, CuxFe3-xO4 (0≤x≤1) which are oxidized in cation deficient spinels CuxFe3-xO4+δ (0≤δ≤0.5) have been performed by TG, DTG, FT-IR and XPS when the copper content determine the number of oxidizable cations 1-x = (Fe2+ + Cu+) per mole of ferrite. It was demonstrated that Fe2+ and Cu+ ions are oxidized into Fe3+ and Cu2+ ions below 300°C and that the availability to diffuse could be envisaged as follows : Cu+B(130°C) < Fe2+B(185°C) < Cu+A(240°C) . For high copper content (≥0.4), the presence of additional interstitial Cu+ ions in tetrahedral sites has also been found.
© EDP Sciences 1997