Tailoring the structural, optical, magnetic, and dielectric properties of yttrium-substituted magnesium ferrite via microwave hydrothermal synthesis

Abstract

The nanostructures of yttrium-substituted magnesium ferrites (MgFe_2-xY_xO₄; where x = 0.0, 0.02, 0.04, 0.06, 0.08, and 0.10) were synthesized using microwave hydrothermal method at a synthesis temperature of 200 °C/60 min. X-ray diffraction (XRD) analysis confirmed a single-phase cubic spinel structure with a space group of Fd-3m for all samples. Morphological studies were examined with field emission scanning electron microscopy (FESEM), revealing a average grain size ranging from 60 nm to 180 nm. The band gap energy (E_g) calculated for x = 0.0 is 2.54 eV in tetrahedral bands and 1.84 eV in the octahedral bands. X-ray photoelectron spectroscopy (XPS) was used to analyze the compositional and chemical states of the elements. The saturation magnetization (M_s) value decreased from 18.91 emu/g (x = 0) to 8.41 emu/g (x = 0.10). The coercivity (H_c) is significantly higher for x = 0.02 (22.75 Oe) in comparison to MgFe₂O₄ (1.95 Oe). Dielectric constant (ε′) and loss tangent (tanδ) were measured over a wide frequency range (100 Hz–1 MHz). A significant change in dielectric properties was observed with yttrium substitution; the ε′ decreased from 28 (x = 0.0) to 9 for x = 0.10, while tanδ values ranged from 4.15 (x = 0.0) to 2.54 (x = 0.10).