Characterization and Investigation of Magnetic and Microwave Properties of Multiwalled Carbon Nanotube/SrFe10MnSn0.5Ti0.5O19 Nanocomposites

SrFe₁₀MnSn_0.5Ti_0.5O₁₉/multiwalled carbon nanotube (MWCNT) nanocomposites with different volume percentages of MWCNT content were synthesized by a sol–gel method. The results of x-ray diffraction, field-emission scanning electron microscopy, and Fourier-transform infrared spectrometry analyses demonstrated that the SrFe₁₀MnSn_0.5Ti_0.5O₁₉ nanoparticles were attached on the external surfaces of the MWCNTs. Mössbauer spectroscopy indicates that the substituted cations preferentially occupy the 12k sites. Magnetic properties were measured using a vibrating-sample magnetometer, and microwave absorption properties were investigated using a vector network analyzer. It was found that, with increasing volume percentage of MWCNT content, the saturation magnetization as well as the coercivity decrease, but the reflection loss widely increases. To investigate the effect of sample thickness on the absorption properties, different values of thickness (1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, and 2 mm) were selected. The results showed that, with increasing thickness of the absorber, the reflection loss and bandwidth broadly increase.