RESEARCH ON THE CHEMISTRY AND SINGLE CRYSTAL GROWTH OF MAGNETIC OXIDES

Phase relationships in the liquidus range under different O2 partial pressures are summarized for the system iron oxide-yttrium oxide, and detailed results of phase relations obtained by Al substitution in Y-Fe garnet are presented. Various methods of crystal growing are reviewed, and results of Czochralski growth of Y-Fe garnet are discussed. Subsolidus phase relations are presented for the system FeO-Fe2O3-Al2O3. This system has been studied because of the interest in electrical conductivity processes in magnetite derived spinels. It allows for a trivalent substitution in Fe3O4, compared with the divalent substitutions such as Ni, Co and Mg. Conductivity data obtained on samples of Ni substitutions in magnetite confirm a proposed model describing electrical conductivity in such systems. Cation distribution studies by X-ray intensity measurements and magnetic moment determinations have been made on the terminal composition of Mg substituted magnetite and are reported.