Shape-controlled synthesis of superparamagnetic ZnFe2O4 hierarchical structures and their comparative structural, optical and magnetic properties

Abstract

Herein, we report a prospective strategy to synthesize ZnFe2O4 hierarchical structures assembled by nanoparticles to obtain different morphology like spheres, rods, and flowers. The morphological influence on physicochemical and magnetic properties has been extensively explored. Phase purity of samples was determined by X-ray diffraction (XRD) and morphological and structural features were elucidated with the help of field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopy (HRTEM) with energy dispersive spectroscopy (EDX) tool was used for elemental analysis. FESEM and HRTEM confirmed the formation of ZnFe2O4 with different morphologies. Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy gave the insight of bonding mechanism associated with the synthesized materials. Meanwhile, the material chemistry of obtained products was investigated by X-ray photoelectron spectroscopy (XPS). The surface area of samples with different morphologies have also been found to vary from 19 to 55.8 m2/g while the optical band gap study confirmed that nanorods have smaller band gap having value 2.86 eV when compared to sphere and flower structures with band gap 4 eV and 3.47 eV respectively. Magnetic measurements performed on vibrating sample magnetometer (VSM) ascertains the superparamagnetic behavior of synthesized materials.