Investigation of structural, morphological and optical properties of NiFe₂O₄/<i>α</i>-Fe₂O₃ nanocomposite synthesized by hydrothermal method

Abstract This study highlights the exploration of structural, morphological and optical properties of NiFe 2 O 4 / α -Fe 2 O 3 nanocomposite synthesized by hydrothermal method. Hydrothermal method is a simple, cost-effective, environmentally benign and low temperature method to synthesize nanostructurd materials with high purity, and controlled particle size and morphology. The synthesized material was investigated for thermal, structure formation, morphology and optical behaviour using thermogravimetric analysis (TGA), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, field-emission scanning electron microscopy (FE-SEM) and Ultraviolet-Visible (UV–vis) spectroscopy. TGA studies revealed that the optimal calcination temperature to produce impurity free nanocomposite is above 400 °C. XRD studies approved the crystalline nature of the nanocomposite material with NiFe 2 O 4 and α -Fe 2 O 3 phases. XRD results also authenticated the cubic crystal structure of NiFe 2 O 4 and rhombohedral strucrure of α -Fe 2 O 3 . Raman spectroscopy measurements confirmed the coexistence of both NiFe 2 O 4 and α -Fe 2 O 3 materials in the NiFe 2 O 4 / α -Fe 2 O 3 nanocomposite. The spherical morphology of the particles was confirmed from FE-SEM studies and the average size of the particles was estimated to be 48 nm. The indirect optical energy band gap of the NiFe 2 O 4 / α -Fe 2 O 3 nanocomposite obtained from UV–vis studies was found to be 1.86 eV.