Magnetic and optical property studies on cubic Gd3Fe5−xCoxO12 nanogarnets for spintronics

Abstract

Investigations on wide band gap nanocrystalline magnetic materials are the subject of recent research interest for establishing functional spin-based nanodevices. In this regard, gadolinium-based rare earth garnets (Gd₃Fe_5−xCo_xO₁₂) were processed in the form of nanostructures by a facile chemical route involving high-temperature annealing treatments. The garnet configuration and the existence of secondary phase characteristics were identified using Raman and X-ray diffraction analysis, respectively. The average size of the nanoparticles was estimated to be around 50–60 nm using Scherrer's formula and further confirmed using scanning/transmission electron microscopy imaging techniques. The wide band gap of Gd₃Fe_5−xCo_xO₁₂ systems was studied using the Tauc plot extracted from UV-vis absorbance measurements. A broad luminescence was also observed along the ultraviolet and green regions of the photoluminescence spectrum, which was attributed to the intermediate defect levels existing within the band gap of the material. The electrochemical characteristics of the Gd₃Fe_5−xCo_xO₁₂ nanostructures were further identified using the Nyquist-type impedance plots. Additionally, the saturation magnetization observed in the room-temperature magnetic (M–H) measurements was attributed to the complex magnetic structure of the garnet. Finally, in the present study, the investigation results suggest Gd₃Fe_5−xCo_xO₁₂ as an ideal candidate for applications in magneto-optical devices and spintronics.