Influence of pH on the structural, magnetic and optical properties of SrFe2O4 nanoparticles
S. E. Mousavi Ghahfarokhi, E. Mohammadzadeh Shobegar
Abstract
Strontium spinel ferrite nanoparticles (SrFe2O4) were prepared by the sol–gel method using precursors with different pH values. The morphology and structure of the samples were characterized by field emission scanning electron microscopy (FESEM), and X-ray diffraction (XRD). The results of X-ray diffraction patterns showed that the ferrite phase was formed in all samples. The average crystallite size was calculated by the Scherer formula and the average crystallite size about 20 nm is obtained. The results of the analysis (FT-IR) show that the samples consist of tetrahedral and octahedral sites. The optical properties using UV–vis spectrophotometer were studied. From optical characterization, it was found that the band gap decreases as the pH increases from 1 to 9. The magnetic properties of the nanoparticles were measured by vibrational sample magnetometer (VSM) and showed that by increasing pH, the value of the Hc is decreased. These changes in the Hc are related to size change, distribution of ions, tilting, and anisotropy effects.