Abstract
Nickel ferrite (NiFe2O4) nanoparticles were prepared using sol–gel technique; while Polyaniline (PANI)/NiFe2O4 nanocomposites were synthesized via chemical oxidative polymerization of aniline monomer (ANI) in the presence of various ferrite amounts (nickel ferrite/ANI=2.5, 5, 25 and 50wt%). The morphology, structure, magnetic, electrical and microwave absorption properties of ferrite powders and nanocomposites were characterized by Fourier transform infrared (FTIR), powder X-ray diffraction (XRD), UV–vis absorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), four-point probe resistivity instrument and vector network analyzer. The crystalline size of nickel ferrite was found in the range of 23–27nm. The results of TGA, FTIR and UV–vis spectra indicated that nickel ferrite particles improved the thermal stability of composite, and there were interactions between ferrite particles and PANI. The nanocomposites under applied magnetic field exhibited the hysteresis loops of ferromagnetic nature at room temperature. The conductivity of all measured samples decreased with decreasing temperature, exhibiting typical semiconductor behavior. The microwave absorbing properties of the nickel ferrite and composite specimens with the coating thickness of 2mm were investigated using waveguide method in the frequency range of 1–6GHz. The results showed a microwave absorption band with frequency shifts to the higher frequency region with the increase in PANI content. The maximum reflection loss reaches −12.5dB at 2.5GHz for the nickel ferrite and −20.3dB at 3.78GHz for the composite containing 95wt% aniline. The electronic and magnetic properties of the nanocomposites are tailored by controlling the ferrite content.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.