Improvement in magnetic, optical and dielectric behavior on erbium addition to Mg0.5Mn0.5Fe2O4 for device applications

Abstract

The ferrite samples Mg_0.5Mn_0.5Fe_2-xEr_xO₄ (x = 0, 0.02, 0.04, 0.06, 0.1) prepared using the solid-state route were evaluated for microwave absorption applications. X-ray diffraction with Rietveld refinement revealed multiphase characteristics and the coexistence of a spinel phase with an orthorhombic phase attributed to the larger Er³⁺ ionic radius. The SEM analysis of rare earth-doped spinel ferrites reveals that grain size and porosity are significantly influenced by doping concentration, which in turn strongly affect the dielectric and magnetic properties. AFM indicated high surface roughness. The favourable figures of dielectric constant and loss factor recorded at frequency variation makes the material suitable in high frequency performances. The Er modified ferrites possessing a broad range of relaxation period can interact and effectively absorb an extended range of spectrum from the microwave frequency range. UV–Vis spectroscopy demonstrated an increase in the optical forbidden band gap from 1.06 eV to 2.30 eV after doping of erbium, enhancing light absorption. The combined improvements in optical, dielectric, and thermal properties confirm that Er-modified ferrites are promising candidates for high-frequency, high-temperature microwave absorbing applications. The increase of coercivity with respect to doping concentration may be attributed to the anisotropy due to the strong spin orbit coupling of Er³⁺.