Novel Gadolinium (Gd) and Chromium (Cr) Co-Doped Yttrium Iron Garnet (Y3Fe5O12) Nanoparticles

In this study, gadolinium (Gd) and chromium (Cr) co-doped yttrium iron garnet (Y3Fe5O12) nanoparticles were prepared by the sol–gel method. The X-ray diffraction (XRD) data, which was further refined by Rietveld analysis, proved the cubic (Ia-3d) structure without any secondary phase. Surface morphology and microstructure analysis were investigated utilizing field emission scanning electron microscopy (FESEM). FESEM images show how dopants (both Gd and Cr) particles have dispersed non-uniformly in the Y3Fe5O12 matrix and the nanostructured particles with size range from 97 to 284 nm for different Gd and Cr levels. Ferroelectric measurements present a substantial improvement in polarization under a saturated applied field of ± 5 kV/cm for doped, and co-doped Y3Fe5O12. At room temperature magnetic properties are measured by VSM, and it is found that the magnetic properties (saturation and remnant magnetization) are reduced (enhanced) with Gd3+ (Cr3+) doping substantially. UV–VIS spectrophotometry revealed a significant reduction in optical band gap energy from 2.23 to 1.99 eV due to Gd and Cr co-doping in Y3Fe5O12. The dielectric behavior of Y3Fe5O12 is studied in the 100 Hz to 1 MHz frequency range. The frequency-dependent dielectric constant displays the normal dielectric dispersion response, which is explained in terms of polarization concentration using Maxwell–Wagner theory. The dielectric constant is independent of the frequency at longer wavelengths (˃ 105 Hz), owing to only ionic and electronic polarizations. The AC conductivity (σAC) complies with the power law, and the linearity of log2 versus logσAC plot shows that the conduction mechanism is due to limited polar hopping. The obtained results anticipated that Gd3+- and Cr3+-doped Y3Fe5O12 exhibit improved properties for application compared to pure Y3Fe5O12. The synthesized ceramics may find potential applications in sensors, capacitors, actuators, transducers, and memory devices.