Tunable magnetic coupling and dipole polarization of core-shell Magnéli Ti₄O₇ ceramic/magnetic metal possessing broadband microwave absorption properties

There are few reports on the application of Magnéli Ti₄O₇ in the field of electromagnetic wave absorption. Herein, we designed and prepared a Ti₄O₇/magnetic metal composite via an electrostatic assembly with in-situ reduction reaction. This system utilized distinct magnetic coupling deriving from the subtle designed structures and magnetic-dielectric synergy. The core-shell magnetic metallic nanoparticles/oxygen deficient Ti₄O₇ are useful microwave absorbers in terms of wide broadband, strong absorption and ultra-low filler amount. The optimal reflection loss of Ti₄O₇@CoNi composite was −43.6 dB at 2.5 mm, meanwhile the effective absorbing band could reach over 5.12 GHz at only a 2.7 mm thickness. The results confirm that the dependence of the electromagnetic characteristics of the absorber on the filler ratio, frequency, and absorber thickness. Therefore, this work may be beneficial in constructing core-shell structured magnetic metal/Magnéli Ti₄O₇ composites to tune electromagnetic parameters and strengthen electromagnetic absorption.