Development of uniaxial magnetocrystalline anisotropy in SrFe12−x(DyGd)xO19 thin film synthesized by incorporation of high coercivity nanoparticles in sol-gel method

SrFe12−x(DyGd)xO19 thin films with x=0-2.5 were synthesized by a sol-gel method on thermally oxidized silicon wafer (Si/SiO2). XRD patterns and FE-SEM micrographs demonstrated that single phase c-axis hexagonal ferrite films with rather narrow grain size distribution were obtained. It was found that the grain size is decreased from about 110 nm (for the film with no substitution) to 35 nm (for the film with the highest amount of substitution cations). AFM micrographs exhibited that the surface roughness decreases with an increase in substitution content. It was found from the VSM graphs that with an increase in substitution contents coercivity and saturation of magnetization increase. The maximum saturation of magnetization and coercivity at perpendicular direction were 250 emu/g and 5.5 kOe, respectively.