Investigations on structural, magnetic properties of lithium zinc ferrites and radar absorbing properties of ferrite-polymer composites

Abstract

In this work, Li_0.5–0.5xZn_xFe_2.5–0.5xO₄ (0.1 ≤ x ≤ 0.8) ferrite system with a cubic crystal structure was synthesized using standard ceramic technology. The phase composition, structure, morphology and magnetic properties of the synthesized materials were analyzed. Synthesis conditions for obtaining single-phase ferrites were determined. It is shown that substitution of the ${\text{Li}}_{0.5}^{1+}{\text{Fe}}_{0.5}^{3+}$ complex with divalent Zn²⁺ cations significantly affects the magnetic properties and Curie temperature of the materials. Composites based on lithium-zinc ferrites with a high filler content were manufactured and their electromagnetic properties were studied. The dependence of the natural ferromagnetic resonance frequency of the composites on the filler composition was determined. For the first time, two-layer absorbing coatings have been developed, where the first layer is made of composites based on lithium-zinc ferrites, and the second layer is based on planar Y-type hexaferrite. Their absorption properties have been studied in the frequency range from 10 MHz to 18 GHz. It has been determined that two-layer composites are more effective absorbers of electromagnetic pollution in a wide frequency band at a level of less than minus 10 dB, compared to single-layer materials of similar composition and thickness.