Studies of the co-precipitation method-synthesized ZnO/CoFe₂O₄ nanocomposites structural, dielectric and magnetic characteristics for high-frequency application

The co-precipitation technique is employed for preparing ZnO/CoFe₂O₄ composites. X-ray diffraction, Fourier Transform Infrared Spectroscopy (FTIR) and Rietveld refinement techniques is performed to investigate the composite structure obtained after annealing. The Rietveld refinement method gives information about crystalline phases present in the sample. Rietveld analysis of X-ray diffraction results reveals the presence of two phases where phase 1 is zinc oxide with hexagonal structure, whereas phase 2 is cobalt ferrite with cubic structure. XRD shows the size of crystallites for phase 1 is 43 nm, and for phase 2 is 38 nm. FTIR peaks centered at 440–515 cm⁻¹ corresponds to M–O stretching vibrations. Dielectric properties such as ε′, ε″, Tanδ, conductivity, and electric modulus of the sample have been measured at temperature 30–300 °C and the frequency range is 1–10⁷ Hz. Dielectric parameters show dependence on frequency and temperature as well as on concentration and temperature used for synthesis of samples. Synthesized sample at temperature 400 °C and concentration 1:1 shows highest value of ε′ i.e., above 1000. To study magnetic properties VSM characterization is used. High value of ε′, Tan δ and remarkable low value of conductivity (high resistivity), retentivity (0.01–2.17 emu/g) and coercivity (34.8–213 Oe) indicate its application in high frequency devices.