STRUCTURE OF NANOCRYSTALLINE SPINEL FERRITE PRODUCED BY HIGH-ENERGY BALL-MILLING METHOD. V. Sepelak¹, A. Yu. Rogachev², U. Steinike³, D.-Chr. Uecker³, S. Wissmann⁴ and K. D. Becker⁴, ¹ Institute of Geotechnics of the Slovak Academy of Sciences, 04353 Kosice, Slovak Republic, ²Institute of Solid State Chemistry of the Russian Academy of Sciences, K 630091 Novosibirsk, Russia, ³Institute of Applied Chemistry e.V., 12484 Berlin, Germany, ⁴Institute of Physical and Theoretical Chemistry, Technical University of Braunschweig, 38106 Braunschweig, Germany

First mechanochemical synthesis (synthesis induced by a high-energy ball-milling process) of zinc ferrite from zinc oxide and iron oxide powders at room temperature is presented. Structure of the formed zinc ferrite with a large amount of strain and defects introduced during the mechanical treatment is characterized by means of X-ray powder diffraction, scanning electron microscopy, and Mössbauer spectroscopy. The ball-milling of the ZnO/Fe₂0₃ mixture in a planetary mill results in the formation of zinc ferrite with non-equilibrium distribution of cations between tetrahedral and octahedral positions [1,2]. Subsequent thermal treatment of the disordered zinc ferrite leads to its crystallization at temperatures, which are by about 300 K lower than those at which the crystalline zinc ferrite is formed by a conventional thermal method commonly involving solid-state reactions.

[1] Sepelak, V., Steinike, U., Tkacova, K., Uecker, D.-Chr., Richter-Mendau, J., Jancke, K., Buchal, A., Rykov, A. I., Rogachev, A.Yu.: Z.Kristallogr.Suppl. 8 (1994) 673.

[2] Sepelak, V., Tkacova, K., Steinike, U., Boldyrev, V.V.: European Powder Diffraction Conference EPDIC-4, Chester 1995, Mat.Sci.Forum 1996, in press.