Detailed investigation of the structural and electrical properties of ZnO/Fe₃O₄ nanocomposites

Abstract

Abstract The nanocomposites with the formula (1-x)ZnO+xFe 3 O 4 (x = 0, 0.01, 0.03, 0.05, 0.7 and 0.09) were prepared using the sonomechanical method, while the pristine ZnO and Fe 3 O 4 were prepared using the co-precipitation technique. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), and a high-resolution broadband impedance analyzer were used to examine the structural, microstructure, and dielectric properties of the investigated samples. XRD analysis assures the wurtzite hexagonal structure of ZnO for all nanocomposite samples. The FTIR showed the existence of a functional group of ZnO and Fe 3 O 4 . The ac conductivity, dielectric constant ( ε ′), dielectric loss ( ε ′), electric modulus, impedance, and Nyquist plot were studied as a function of frequency and at different temperatures. The results show that the small concentration of Fe 3 O 4 affects the ac conductivity and dielectric properties. The Koops phenomenological theory and the Maxwell-Wagner interfacial model were used to analyze the observed dielectric dispersion. The analysis of modulus and impedance results indicated the existence of non-Debye relaxation and the involvement of both grains and grain borders in polarization. The impedance study reveals that just one semicircle is observed in all samples, indicating that the influence of grain boundaries is more significant than the contribution of grains.