Extra-wide bandwidth via complementary exchange resonance and dielectric polarization of sandwiched FeNi@SnO2 nanosheets for electromagnetic wave absorption

Abstract

Advanced electromagnetic (EM) wave absorbers with wide bandwidth is crucial to avoid EM interference and radiation, while achieving compensational attenuation at different frequencies is challenging. Herein, two-dimensional (2D) sandwiched FeNi@SnO2 have been designed, for which SnO2 nanosheets provide numerous heterogeneous nucleation sites for the growth of dispersive FeNi nanoparticles with reduced size. The SnO2 exhibits dipole polarization at 21.45 GHz with a width of ∼4.00 GHz, while the FeNi nanoparticles induce exchange resonance at 18.13 GHz (∼6.00 GHz width) and interfacial polarization at 15.97 GHz (∼6.00 GHz width). Such complementary attenuation mechanisms give rise to an impressive ultra-wide effective absorption bandwidth of 11.70 GHz with strong absorption of -49.1 dB at a small thickness of 1.75 mm. Not only superior EM wave absorption is achieved in this work, it also provides a versatile strategy to integrate different loss mechanisms in the design of EM wave absorbers with extra-wide bandwidth.