Rietveld refinement, dielectric and magnetic properties of NBT-Spinel ferrite composites

Ferrite-ferroelectric composites having general formula (1-x)Na0.5Bi0.5TiO3-(x)Ni0.25Mg0.5Zn0.25Fe2O4 were developed by conventional solid state reaction method. The structural, dielectric and magnetic properties were studied for all the prepared samples. The crystalline phases of samples were verified by XRD. Rietveld refinement pattern confirms the coexistence of cubic ferrite phase as well as rhombohedral ferroelectric phase in the composites which make them promising candidate for versatile applications. The tangent loss (tan delta) and dielectric constant (epsilon') both shows dispersion at lower frequencies. From the Nyquist plot of impedance, the effect of grain and grain boundaries on the electrical properties was examined. From Arrhenius plot, it was found that dc conductivity and activation energy of all the compositions increases with increase in temperature. Magnetic parameters were found to be increased as the ferrite phase is increased which provides information regarding the intercoupling between the ferroelectric and magnetostrictive ferrite phases. These ME composites are found to be useful in memory devices. (C) 2019 Elsevier B.V. All rights reserved.