Dielectric, magnetic and ferroelectric studies in (x)Mn0.5Zn0.5Fe2O4 + (1-x)BaTiO3 magnetoelectric nano-composites

Abstract

The Magneto-electric nano-composites, (x)Mn0.5Zn0.5Fe2O4+(1-x)BaTiO3 (x=15%,30%,45%) were synthesized by sintering mixtures of highly ferroelectric BaTiO3 (BT) and highly magnetostrictive magnetic component Mn0.5Zn0.5Fe2O4 (MZF).The presence of two phases in magneto-electric nano-composites were probed by X-ray diffraction (XRD) studies and confirmed their nano crystalline phase. The peaks observed in the XRD spectrum indicated spinel cubic structure for MZF ferrite and tetragonal perovskite structure for BT and, both spinel and pervoskite structures for synthesized nanocomposites without any impurity or intermediate phase. Surface morphology of the samples has been investigated using Field Emission Scanning Electron Microscope (FESEM), which reveals a homogeneous microstructure with uniform dispersion of BT grains. The variation of dielectric constant and dissipation factor as a function of frequency from 100 Hz to 1 MHz at room temperature were carried out using a Hioki LCR Hi-Tester. The dielectric dispersion is observed at lower frequencies due to interfacial polarization arising from the interface of the two phases. At higher frequencies, the dielectric constant is almost constant due to the inability of electric dipoles to follow the quick variation of the alternating applied electric field. The electrical conductivity deduced from the measured dielectric data has been thoroughly analyzed and found that the conduction mechanism in these composites is in conformity with electron hopping model. To study the magnetic and ferroelectric ordering in nano ME-composites, M-H and P-E hysteresis loops were recorded at room temperature.