Effect of rare earth substitution on the structural and electrical properties of Cu–Mg ferrite

Abstract

The samples of Cu 0.9 Mg 0.1 R y Fe 2-y O 4, where y = 0.01 and R = Sm , Dy , Ho and Hf , were prepared by standard ceramic method. All investigated samples were sintered at 1150°C with a heating rate of 4°C/min and sintering time of 8 h. X-ray diffraction study of the compositions revealed the formation of cubic spinel structure with the appearance of small peaks indicating the presence of secondary phases. Seebeck coefficient was obtained from thermo-electromotive force (emf) measurements. The alternation of the Seebeck coefficient sign between (+)ve and (-)ve means that the two conduction mechanisms take place simultaneously. The dielectric parameters such as dielectric constant, quality factor were determined as a function of temperature and at different frequencies. The decrease in Fe 3+ ions on the octahedral site decreased the polarization of the system, through the dielectric transition point.