Magnetic and electrical properties of Ti-substituted yttrium iron garnet

Abstract

We have investigated the possibility of formation of a garnet phase and the magnetic and electrical properties of the systems (a) Y2O3–CaO–Fe2O3–TiO2 and (b) Y2O3–Fe2O3–NiO– TiO2. X-ray data show the formation of single phase up to x=0.7, in the system (a) while the garnet phase could not be prepared in the system (b). Magnetization measurements indicated canting of spins on the tetrahedral sites in the system (a). Curie temperature decreased with increase in x in this system. Change in the activation energy for conduction has been observed near the Curie temperature. Seebeck coefficients were positive and essentially independent of temperature. Electrical properties have been explained on the basis of the model suggested by Austin and Mott. According to this model electron hopping in the octahedral sites may occur by jumping indirectly through tetrahedral site.