STUDY OF THE NONSTOICHIOMETRY AND PHYSICAL-PROPERTIES OF THE SRXDY1-XFEO3-Y FERRITE SYSTEM

A series of samples in the Sr//xDy//1// minus //xFeO//3// minus //y system (x equals 0. 00, 0. 25, 0. 50, 0. 75, and 1. 00) have been produced by heating the reactants to 1200 degree C in air under atmospheric pressure. Mohr salt analysis shows that DyFeO//3 is a stoichiometric compound and that Fe**4** plus ions and oxygen deficiency compensate for the cation charge deficiency which is caused by substitution of Sr**2** plus at Dy**3** plus sites. X-ray powder diffraction assigns the compositions x equals 0. 00 and 0. 25 to the orthorhombic system and the compositions x equals 0. 50, 0. 75, and 1. 00 to the cubic system. The electrical conductivity sharply increases and the activation energy decreases with the presence of mixed iron valency. The Moessbauer spectra of the samples with x equals 0. 25 and 0. 50 are composed of two sets of six lines and a single broad peak for x equals 0. 75.