Dielectric, electrical transport and magnetic properties of (WO3)x/(CuFe2O4)1-x (x = 0.1 to 0.5%) nanocomposites

Abstract

The (WO₃)_x/(CuFe₂O₄)_1-x; x = 10 to 50 wt% nanocomposites were obtained by powder mixing method. The analysis of phase was confirmed by X-ray diffraction (XRD) pattern, which shows the formation of both phases without any impurities. The Scanning Electron Microscope (SEM) images exhibit the cubic morphology of particles with nano-dimensions and the cubic morphology deteriorated with addition of WO₃. The variation of dielectric constant both real (ε^/) and imaginary parts (ε^//) as a function of log ω was measured over the frequency ranging from 1 kHz to 2 MHz. Both ε^/ & ε^// also demonstrate the higher value at low frequency and explained by Koops’s theory. Moreover, ε^/ and ε^// of dielectric constant increases with WO₃ contents. This higher value of dielectric constant makes this nanocomposite (NCPs) a promising material in energy storage devices. The A.C. conductivity (σ_ac) also shows an increasing trend with frequency which is attributed to increase in jumping frequency of charges between Fe²⁺ and Fe³⁺. The real (Z^/) and imaginary (Z^//) parts of impedance decreases at higher frequency ascribed to increase in σ_a.c. The Nyquist plots show one semicircular arc at higher frequency which is attributed to the conduction process produced in grains. The effect of magnetic field on these NCPs was also observed by measuring the M/H loops through Vibrating Sample Magnetometer (VSM) at room temperature. The M/H loops show a typical behavior of ferrimagnetic ceramic with diminish of saturation magnetization (M_s) and coercivity (H_c) with WO₃ contents.