Three dimensional flower like ZnFe2O4 ferrite loaded graphene: Enhancing microwave absorption performance by constructing microcircuits

In the research of new type of absorbing materials, the influence of special three-dimensional (3D) microstructure and the composite effect of multi-component materials on the electromagnetic properties and absorbing properties of materials has attracted widespread attention. In this work, the 3D flower like ZnFe2O4 ferrite (3D-ZFO) was prepared by two solution chemical precipitation processes, and then a simple ultrasonic and heat treatment process was used to uniformly load the prepared 3D-ZFO on graphene nanosheets (GNs). A new wave absorber (3D-ZFO/GNs) composed of two-dimensional (2D) and 3D materials was obtained. Interestingly, the coprecipitation of Fe3+ and Zn2+ in alkaline solution transforms the 3D flower like ZnO template composed of flakes into ZnFe2O4 composed of lines. The combination with GNs can effectively enhance the conductance loss and dipole polarization, and create a new effective hetero interface. In addition, 3D-ZFO with high resistance and GNS with excellent conductivity form a micro circuit, which promotes the formation of micro current and is conducive to the dissipation of electromagnetic wave energy in the form of micro current. In the 2–18 GHz frequency band, 3D-ZFO/GNs with 5 wt% GNs can obtain an effective bandwidth of 5.56 GHz at a matching thickness of 1.5 mm. By controlling the thickness of the matching layer, the absorbing frequency band can be easily adjusted to meet the needs of multi-band absorbing. Considering the simple preparation process, the increase of the electromagnetic wave conduction path by the special microstructure and the synergistic effect of multiple loss mechanisms, we believe that the prepared 3D-ZFO/GNs is expected to be a candidate for high-efficiency microwave absorbers.