Microstructure, Magnetic, and Electrical Properties of Multiferroic Composite

Abstract

Multiferroic nano-composites with chemical formula (x) Ni0.5Mg0.5Fe2O4 (NMFO) + (1-x) BaTiO3 (BTO); (x=10, 20, 30 and 40%) were prepared via sol–gel method. X-ray diffraction (XRD) analysis of (NMFO) phase exhibits a single cubic phase of spinel while (BTO) exhibits a single tetragonal phase of perovskite. XRD of all composite samples showed the coexistence of both phases (cubic and tetragonal). Furthermore, the lattice parameters and crystallite size were calculated. The lattice parameters for (NMFO), (BTO) and their composites are nearly constant which indicates that there is no chemical reaction between constituents. In composite samples, the crystallite size of (NMFO) phase increases while that of (BTO) phase decreases with increasing x-content. High resolution transmission electron microscope (HRTEM) revealed the formation of nano-particles for both (NMFO) and (BTO) phases with average particle size 9 nm and 67 nm, respectively. Moreover, there is a single particle domain for (NMFO) phase where the crystallite size and the average particle size are nearly equal. Field emission scanning electron microscope (FESEM) confirmed that the average grain size increases with increasing x-content. D.C resistivity confirmed the semiconductor behavior of all samples where the resistivity decreases with increasing temperature. Furthermore, Curie temperature (Tc) of all samples were determined from resistivity curves. On the other hand, D.C resistivity decreases by increasing x-content. Electrical permittivity of all samples were examined as a function of frequency in both low and high frequency ranges.