Dielectric polarization and charge transport in Gd-doped Fe3O4 nanocrystals for energy storage and electronic devices

Abstract

Gd-doped magnetite (GdxFe3−xO4) nanocrystals were synthesized via the co-precipitation method with an aim to study the effect of rare-earth substitution on their structure, shape, and dielectric and magnetic properties. Structural analysis using X-ray diffraction revealed that the samples formed a single-phase cubic spinel structure with minor lattice distortion upon Gd substitution. Nanocrystalline materials were characterized as cluster-like grains using field-emission scanning electron microscopy. Fourier transform infrared spectroscopic analysis provided evidence of a spinel structure and revealed metal–oxygen vibrations at the tetrahedral and octahedral sites. From the dielectric analysis, improved dielectric permittivity at lower frequencies, attributed to Maxwell–Wagner interfacial polarization, and lower dielectric loss at higher frequencies indicate their potential for dielectric and energy-related applications. The application of an alternating current to the materials revealed conductivity consistent with the thermally activated hopping mechanism and the correlated barrier hopping model. Magnetic analysis revealed a soft magnetic material with lower coercivity and moderate saturation magnetization. The combined structural, dielectric, electrical, and magnetic characteristics highlight the potential of Gd-doped magnetite nanocrystals for future energy-related and electronic applications.