Microwave and Magnetic Analysis of Substituted SrFe12O19/ Multi-walled Carbon Nanotubes

Substituted strontium ferrites SrFe12-xCrx/2Alx/2O19 (x=0–2.5) / multi-walled carbon nanotubes (MWCNTs) nanocomposites were prepared by a sol- gel method. The XRD patterns show a relatively weak peak at around 26º, corresponding to the graphite (002) lattice plane of the MWCNTs. The peak of Fourier transform infrared spectroscopy (FTIR) at about 1730 cm-1 could be assigned to the stretching mode of carbonyl groups (C=O), indicating the presence of PAA chains in PAA-carbon nanotubes. Field emission scanning electron microscopy (FE-SEM) micrographs revealed that dot array of ferrites on the surface of carbon nanotubes were formed. The magnetic properties confirmed that the values of saturation magnetization for nanocomposites are considerably lower than that of SrFe12-xCrx/2Alx/2O19 nanoparticles. The reflection loss of pure MWCNTs is rather low as compared to the nanocomposites for whole frequencies in the range of 12–18 GHz. It was found that MWCNTs could enhance reflection loss value of ferrites.