Excellent Microwave Absorbing Properties of Nd³⁺-Doped Ni–Zn Ferrite/PANI Nanocomposite for Ku Band

Nd3+-substituted Ni–Zn ferrite nanoparticles are synthesized by the sol–gel autocombustion technique, and their nanocomposite with polyaniline (PANI) is prepared by in situ polymerization. X-ray diffraction patterns confirm the formation of single-phase cubic spinel structure of the prepared ferrite samples. The crystallite size of the synthesized ferrite nanoparticles is found to be in the range of 16−52 nm. The saturation magnetization is observed to decrease due to nonmagnetic polyaniline coating on ferrite nanoparticles. The microwave absorbing properties of ferrite nanoparticles and ferrite/polyaniline nanocomposite are investigated using vector network analyzer in the frequency range of 2−18 GHz for different sample thickness. The minimum value of reflection loss is found to be −6.0 dB at a frequency of 13.20 GHz for Ni0.5Zn0.5Fe1.9Nd0.1O4 ferrite nanoparticles of thickness 2.0 mm, and −53.72 dB at a frequency of 14.48 GHz for Ni0.5 Zn0.5Fe1.9Nd0.1O4/PANI nanocomposite of sample thickness 1.7 mm. The prepared nanocomposite absorbs 99.99% of the incident microwave at a frequency of 14.48 GHz. The microwave absorbing properties improve with a shift of absorption frequency toward higher level for the nanocomposite sample.