Dielectric, magnetic and optical properties of (Bi,Gd)FeO3- Ni0.8Zn0.2Fe2O4 nanocomposites

Abstract

Bi1−xGdxFeO3 (x = 0.00, 0.05, 0.075, 0.10, 0.15, 0.20) (BGFO) and Ni0.8Zn0.2Fe2O4 (NZFO) exhibiting ferroelectric and ferromagnetic phases were synthesized independently by sol gel and auto combustion method respectively. Equal weight proportions were mixed to obtain the multiferroic nanocomposites having the compositional formula 0.5BGFO-0.5NZFO. Rietveld analysis shows the mixing of the constituent phases in the two-phase mixture and confirms the structural transformation of the ferroelectric component from perovskite to the orthorhombic phase when the concentration of Gd addition exceeds x = 0.10 concentration. SEM micrographs of the samples show uniform grain distribution with decreased grain size upto x = 0.10 Gd content and then increases. FTIR studies show the stretching and bending vibrations of the various bonds present in all the samples. Dielectric constant, ε′ and dielectric loss tangent, tanδ measurements shows the dispersion with enhanced behavior with the increase in Gd content. Room temperature M-H loop measurements of all the samples exhibit enhanced magnetization upto x = 0.10 concentration and follow a reducing trend thereafter. Optical absorbances of all the samples were measured and the energy band gaps were calculated from Tauc's plot. The reduction in the values of energy band gap with the increase in Gd addition enhances the optical absorption capability in the visible range. The enhancement in the dielectric, magnetic and optical properties of the nanocomposite samples simultaneously has proved its viability in various applications, making it a new technological ingredient for future smart materials.