Correlation between site preference and magnetic properties of substituted strontium ferrite thin films

SrFe12−x(Sn0.5Zn0.5)xO19 thin films with x=0−5 were synthesized by a sol–gel method on thermally oxidized silicon wafer (Si/SiO2). The site preference and magnetic properties of Zn–Sn substituted strontium ferrite thin films were studied using 57Fe Mössbauer spectroscopy and magnetic measurements. Mössbauer spectra displayed that the Zn–Sn ions preferentially occupy the 2b and 4f2 sites. The preference for these sites is responsible for the anomalous increase in the magnetization at high Zn–Sn substitutions. X-ray diffraction (XRD) patterns and field emission scanning electron microscope (FE-SEM) micrographs demonstrated that single phase c-axis hexagonal ferrite films with rather narrow grain size distribution were obtained. Vibrating sample magnetometer (VSM) was employed to probe magnetic properties of samples. The maximum saturation of magnetization and coercivity at perpendicular direction were 265 emu/g and 6.3 kOe, respectively. It was found that the complex susceptibility has linear variation with static magnetic field.

Research highlights
► The site preference and magnetic properties of Zn-Sn substituted strontium ferrite thin films were studied using 57Fe Mössbauer spectroscopy and magnetic measurements.
► Mössbauer spectra displayed that the Zn-Sn ions preferentially occupy the 2b and 4f2 sites.
► It is observed that with an increase in substitution content in the ferrite thin films, the coercivity along with saturation magnetization increased, while the magnetic interaction is reduced.
► It was found that effective magnetic susceptibility has linear variation with static magnetic field.