Dependence of pH Variation on the Structural, Morphological, and Magnetic Properties of Sol-Gel Synthesized Strontium Ferrite Nanoparticles

Abstract

In this research work, an attempt of regulating the pH as a sol-gel modification parameter during preparation of SrFe 12 O 19 nanoparticles sintered at a low sintering temperature of 900 C has been presented. The relationship of varying pH (pH 1-14) on structural microstructures and magnetic behaviors of SrFe 12 O 19 nanoparticles was characterized by X-ray diffraction (XRD), field emission scanning microscope (FESEM), thermogravimetric analysis (TGA), Fourier-transform infrared (FTIR), and vibrating-sample magnetometer (VSM). The single-phase SrFe 2 O 19 with optimum magnetic properties can be obtained at pH 1 with a sintering temperature of 900 C. As pH values increase, the presence of impurity Fe 2 O 3 was observed. TGA data-varying pH shows that the total weight loss of most samples was at 30.44% which corresponds to the decomposition process. The IR spectra showed three main absorption bands in the range of 400-600 cm À1 corresponding to strontium hexaferrite. SEM micrographs exhibit a circular crystal type of strontium ferrite with an average crystal size in the range of 53-133 nm. A higher saturation magnetization M s , remanent magnetization M r , and hysteresis H c were recorded to have a large loop of 55.094 emu/g, 33.995 emu/g, and 5357.6 Oe, respectively, at pH 11, which make the synthesized materials useful for high-density recording media and permanent magnets.

Single-Domain Hard Ferromagnetic M-SrFe Nanoparticles for Magnetic Data Storage

“…The calculated cell parameters are: a = b = 5.869 Å, c = 23.007 Å, volume V = 686 Å 3 and ratio c/a = 3.9. The volume of the cell is calculated using the following equation (4) [4,27]:…”

“…In spite of large external magnetic fields, hard ferrite magnets have excellent electrical isolation properties and are difficult to demagnetize [3]. Hard magnetic material with a ferromagnetic structure called M-type hexagonal ferrite is typically utilized to make permanent magnets [4] and in high-frequency equipment and microwave components [5]. A hexagonal ferrite's intrinsic magnetic characteristics of the M-type phase determine its magnetism.…”