Microstructure and Magnetic Properties of SrFe Nano-sized Powders Prepared by Sol-Gel Auto-combustion Method with CTAB Surfactant

In this research, nano-sized powders of strontium hexaferrite were synthesized by sol-gel auto-combustion route using stoichiometric ratio of Fe/Sr. The effect cetyltrimethylammonium bromide (CTAB) addition on microstructure and magnetic properties of hexaferrite have been studied. The samples were characterized using X-ray diffraction (XRD), dynamic light scattering (DLS), vibration sample magnetometer (VSM), field emission scanning electron microscope (FESEM), and transmission electron microscope (TEM) techniques. The results revealed that CTAB addition causes a noticeable reduction in the amount of residual alpha-Fe2O3 phase, since presence of CTAB in the sol facilitates the entrance of Sr2+ ions into the reactions of hexaferrite formation. Also, the morphology of the particles was affected by CTAB addition. Irregular-shaped nanoparticles were synthesized without CTAB additions, while platelet-shaped nanoparticles were obtained by CTAB addition. The mechanism of strontium hexaferrite nanopowder formation has been explained. Magnetic measurements in the sample calcined at 800 A degrees C for 1 h represented that CTAB addition increased the coercivity force ((i) H (c)) from 4.9 to 5.2 kOe and maximum magnetization (M (max)) from 48.4 to 60.4 emu/g, respectively.