Tuning optical and dielectric properties of strontium-zinc ferrite nanomaterials through structure-cation engineering

Herein, SrxZn1−xFe2O₄ nanoparticles produced by chemical co-precipitation are examined to determine how strontium (Sr) doping affects their structural, morphological, optical, and dielectric characteristics. The creation of a single-phase cubic spinel structure was verified by X-ray diffraction, and peak shifts indicated lattice expansion brought on by the addition of Sr. A homogeneous grain morphology with nanoscale dimensions was found by FESEM investigation. The metal-oxygen vibrational modes in the Raman and FTIR spectra showed changes that suggested local structural distortion. With a lowered optical bandgap of 2.62 ± 0.1 eV, UV-Vis spectroscopy revealed a red shift in the absorption edge, improving semiconducting properties. AC conductivity and complex modulus tests revealed improved charge transport and relaxation behavior, whereas impedance spectroscopy indicated decreased dielectric loss (tan δ) at high frequencies. Mössbauer spectroscopy revealed that doping resulted in a redistribution of Fe2+ between tetrahedral and octahedral sites. According to these results, Sr-doped ZnFeO₄ is a promising material for use in high-frequency and optoelectronic device applications. This work develops a structure-cation engineering approach, where Mössbauer spectroscopy validates cation redistribution, allowing for simultaneous tuning of optical and dielectric properties, providing a new avenue for the development of ferrite-based optoelectronic and energy storage materials.