Rare earth iron garnets and rare earth iron binary oxides synthesized by microwave monomode

Abstract

Rare earth iron garnets (R3Fe5O12 or RIG, with R=Y, Sm, Eu, Gd, Dy, Ho, Er, and Yb) and rare earth orthoferrites RFeO3 have been synthesized from R2O3/Fe3O4 mixtures using the monomode microwave (MW) method. Such binary compounds are formed at a low temperature (T<900 K), in a few minutes at ambient atmosphere, whereas under conventional solid state reactions, all these binary oxides are synthesized at a much higher temperature (∼1800 K). The experimental conditions leading to nearly pure RIG are briefly discussed in relation to the nature of the rare earth and to the ratio R2O3/Fe3O4 in the starting mixture. This experimental method was extended to the synthesis of lanthanum- and cerium-doped yttrium iron garnet compounds. These results show that MW is a practical and economical procedure for chemical syntheses.