Optical and magnetic studies of Co_0.7Zn_0.3Fe₂O₄ spinel ferrites with Dy³⁺ substituted for the application of sensors prepared through sol–gel process

Dysprosium (Dy³⁺) substituted cobalt-zinc spinel ferrites were synthesized having composition (Co_0.7Zn_0.3 Dy³⁺ xFe_2−xO₄) with the concentration ranges from (0.00, 0.5, 0.10, 0.15, and 0.20) by using the Sol–Gel synthesis. XRD analysis confirmed the FCC spinel structure of the prepared samples. Lattice constant and X-ray density were calculated in variance ranging from 8.40–8.46 Å and 5.28–5.77 g/cm³, respectively. Fourier Transformation Infrared Spectroscopy (FTIR) were used to measure the frequency band in between 411–562 cm⁻¹ for the tetra and octahedral positions. Scanning electron microscopy was used to study the surface morphology of the prepared samples. The field emission transmission electron microscopy (FE-TEM) was used for the confirmation of particle size. The calculated value of crystalline size was 13 nm, while particle size was the best on 23 nm. It was observed that, on applied field frequency the dielectric parameters exhibits decreasing trend. Magnetic properties were examined by Vibrating Sample Magnetometer (VSM) method and found out saturation magnetization (63.99 emu/g), anisotropy (K) (5366.82 J/m³) and magnetic moment (2.77) were in decreasing while retentivity (2.38 emu/g), squareness ratio (0.07) and coercivity H_c (133.71Oe) were in increasing trend respectively. These features of Dy³⁺ substituted Co–Zn spinel ferrites recommend their better use in sensors and high frequency devices.