(Y0.82La0.18)3Fe5O12–x: Structure and Transport Properties

Abstract

The nonstoichiometry in well-known rare-earth metal ferrite garnets is discussed in the concept of a mayenite analogue. Crystals are grown by floating zone method in different atmospheres. The content of oxygen during the growth process determines its crystal structure: only in an oxygen atmosphere (7 atm) is it possible to obtain a single-phase crystal. The phase decomposes with precipitation of iron oxide when the content of oxygen is lower. The decomposition is also induced by the replacement of Y with a large cation La in Y3Fe5O12. The fibers of the perovskite phase form along the crystal growth direction. The high mobility of anions and electron conductivity are shown by the method of isotopic equilibration with the gas phase on single-crystal garnet composites.