Novel dielectric resonance of composites containing randomly distributed ZrB2 particles with continuous dual-peak microwave absorption

TL;DR

This study reveals a novel dielectric resonance in ZrB2-based composites caused by mesoscopic cluster structures, enabling dual-peak microwave absorption through controlled electron transport, advancing the design of microwave absorbing materials.

Contribution

It introduces a new mesoscopic architecture approach to induce dielectric resonance and dual-peak microwave absorption in composites containing ZrB2 particles.

Findings

Dielectric resonance is plasmonic, driven by electron transport between ZrB2 particles.

Resonance can be tuned or suppressed by adjusting ZrO2 coating ratio.

Dual-peak absorption results from interference effects linked to the resonance.

Abstract

Substantial efforts have been devoted to the elaborate component and microstructure design of absorbents (inclusions) in microwave absorbing (MA) composite materials. However, mesoscopic architectures of composites also play significant roles in prescribing their electromagnetic properties, which are rarely explored in studies of MA materials. Herein, a composite containing randomly distributed ZrB2 particles is fabricated to offer a mesoscopic cluster configuration, which produces a novel dielectric resonance. The resonance disappears and reoccurs when ZrB2 is coated with the insulating and semiconductive ZrO2 layer respectively, suggesting that it is a plasmon resonance excited by the electron transport between ZrB2 particles in clusters rather than any intrinsic resonances of materials constituting the composite. The resonance strength can be regulated by controlling the quantity of the electron transport between particles, which is accomplished by gradually increasing the insulating ZrO2-coated ZrB2 ratio x to disturb the electron transport in ternary disordered composites containing ZrB2 and insulating ZrO2-coated ZrB2. When x exceeds 0.7, the electron transport is cut off completely and the resonance thus disappears. The resonance induces unusual double quarter-wavelength interference cancellations or resonance absorption coupled with quarter-wavelength interference cancellation, giving rise to continuous dual-peak absorption. This work highlights the significance of mesoscopic architectures of composites in MA material design, which can be exploited to prescribe novel electromagnetic properties.