Impact of Process Parameters and Dopant Concentration on Structural, Magnetic, and Dielectric Properties of Dysprosium-doped Nickel-Zinc Ferrites Synthesized by Microwave Hydrothermal Method

Abstract

This study aims to investigate the impact of substituting Dy3+ ions on the structural, magnetic and dielectric properties of Nickel Zinc (Ni-Zn) ferrites, which have the chemical formula Ni0.5Zn0.5DyxFe2-xO4 (where x = 0, 0.01, 0.03, 0.05, 0.07, and 0.09). These ferrites were synthesized using a microwave hydrothermal technique with different process parameters. Structural characterization of the synthesized powders was carried out using X-ray diffraction (XRD) and Fourier transformation infrared spectroscopy (FTIR). The XRD analysis confirmed the presence of a pure spinel phase for Dy concentrations (x) up to 0.05. However, when x ≥ 0.07, an additional orthoferrite phase (DyFeO3) was observed along with the spinel phase. FTIR spectra revealed a shift in low-frequency wave numbers due to Dy3+ ion substitution. The size and morphology of the synthesized powder particles were examined using field emission scanning electron microscopy (FESEM). The powder compacts were sintered using microwave processing at 900 °C for 40 min. The increase in dc. resistivity is observed with an increase in Dy3+ concentration, mainly due to the change in the hopping mechanism with the substitution concentration. Dielectric properties such as dielectric constant and loss are measured in the frequency range of 100 Hz to 1.8 GHz. The high value of dielectric constant and loss observed in the low-frequency region compared to the high-frequency region. Maxwell’s Wagner model and ‘Koop’s theory explains the variation in dielectric properties with the frequency. The magnetic hysteresis loops were measured at different temperatures and observed to enhance the low-temperature magnetic properties compared to room temperature. The results suggest that the magnetic and dielectric properties of the investigated samples can be adjusted by varying the concentration of Dy3+ ions, providing the ability to tailor these properties according to specific application requirements.

Tunable Magnetic and Dielectric Properties of BaMg0.4Al0.4Fe11.2O19 and SiO2 Composites for High-Frequency Applications

“…The low cost of required equipment and the simple steps of the sol-gel auto-combustion method attract people to prepare ferrite nanoparticles. [23][24][25] On the other hand, Ramesh et al 26,27 prepared the garnet samples using techniques like microwave hydrothermal and microwave sintering. They successfully reduced the formation temperature to around 300 °C, and the time was reduced to one-twentieth.…”