Effect of annealing temperature on structural, microstructural, and Mössbauer properties of MgFe2O4 ferrite for photo anode application

The spinel MgFe2O4 ferrite was synthesized using a sol-gel auto-combustion technique at 650 °C, 750 °C, and 1050 °C for 4 h. Instrumental techniques including Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), vibrating sample magnetometry (VSM), Mössbauer spectra and low frequency dielectric measurements were used for characterization of heated samples. The absorption bands in the wavenumber range of 531–400 cm–1 for all samples are due to the Fe3+ - O2- stretching vibrations. XRD analysis of all samples were consistent with a pure spinel phase with crystallite size of 28 nm to 38 nm, except the sample heated at 650 °C which exhibited a small quantity of α-Fe2O3. SEM analysis showed that the morphology changed with heating temperature. Dielectric studies of all samples within the frequency range 100 Hz to 2 MHz at room temperature indicated frequency-dependent phenomena. Furthermore, its application in dye sensitized solar cells was also explored, with a 4.2% power conversion efficiency obtained.