Investigation of microwave absorption property of the core–shell structured Li0.4Mg0.6Fe2O4/TiO2 nanocomposite in X-band region

• Li0.4Mg0.6Fe2O4 is a new spinel ferrite.
• The synthetic procedure is simple and cost effective.
• The composite shows core–shell morphology.
• The composite shows good magnetic, optical and microwave absorbing properties.
• The material shows the maximum reflection loss of −41.6 dB. The thickness of the absorber is only 2.5 mm.

Initially, we have synthesized a magnetic spinel-type ferrite, Li0.4Mg0.6Fe2O4 (LMF) by a simple chemical coprecipitation method. The LMF particles of different sizes were formed, and the most populated size range is 45–75 nm. Further, the LMF was coated by titanium di-oxide (TiO2) via the sol–gel process, and examined the microwave absorption property of TiO2 coated LMF (Ti@LMF) in the X-band region. The formation of both LMF and Ti@LMF was supported by analysing the materials through different analytical techniques such as X-ray diffraction analysis (XRD), X-ray photoelectron spectroscopy (XPS), and fourier transform infrared (FTIR) spectroscopy. The core–shell morphology of Ti@LMF was confirmed by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) analysis. The result indicates that the average shell thickness is around 40–50 nm. The optical and magnetic property was studied by UV–VIS spectroscopy and SQUID analysis. Ti@LMF showed excellent microwave absorption property under the thermoplastic polyurethane (TPU) matrix. The maximum reflection loss (−41.6 dB) was measured with the help of Vector Network Analyzer, and the mechanism of absorption was explained by considering the relative complex permittivity and permeability of the prepared materials. The matching of both the dielectric loss (initiated by TiO2) and magnetic loss (initiated by LMF) is the main reason for remarkable microwave absorption property of Ti@LMF.