Structural, dielectric and impedance spectroscopic studies of (CoZnSmFe₂O₄)_1-x/(MWCNTs)_x nanocomposite for energy storage applications

The functionalization of spinel ferrites with Multi-walled carbon nanotubes (MWCNTs) has made significant attention due to their remarkable synergistic properties leading to a range of promising technological applications. In this research work, the CoZnSmFe₂O₄ nanoparticles were synthesized via the sol gel auto combustion procedure. To prepare their nanocomposites with MWCNTs (i.e. (CoZnSmFe₂O₄)_1-x/(MWCNTs)_x; x = 0, 5, 10, 15, 20 wt%), ultra-sonication process was used with a suitable amount of toluene as a dispersal medium for the functionalization of nanoparticles and MWCNTs. The X-ray diffraction (XRD) analysis revealed that the nanocomposites exhibited well defined single phase crystalline structure. Fourier-transform infrared spectroscopy (FTIR) studies clarified the vibrational modes of the prepared nanocomposites confirming the successful integration of MWCNTs with nanoparticles. Transmission electron microscopy (TEM) investigations provided valuable insights into the morphology and dispersion of nanoparticles within the MWCNTs matrix. The dielectric and impedance measurements were investigated in the frequency range of (25 Hz to 2 MHz). The dielectric parameters of the prepared nanocomposites including dielectric constant, dielectric loss, tangent loss and Ac conductivity have been remarkably increased with wt% of MWCNTs as compare to pure nanoparticles. The real and imaginary part of impedance were decreased with increasing wt% of MWCNTs. The magnetic properties studied using vibrating sample magnetometer (VSM) in the applied magnetic field ranging from (-20–20 kOe). The magnetic parameters such as saturation magnetization (M_s), remanence magnetization (M_r), squareness (M_r/M_s), coercivity (H_c), anisotropy constant (K) and initial permeability (μ_i) of the nanocomposites were investigated. The significant changes in dielectric and magnetic properties of the prepared (CoZnSmFe₂O₄)_1-x/(MWCNTs)_x nanocomposites suggested that they can be used in future energy storage applications.