Dimensional design of Fe0.9Co0.1 nano-alloys with enhanced low-frequency microwave absorption

Abstract

Low-frequency microwave absorbing materials are critical for enabling radar stealth and interference resistance in gigahertz communication devices and electronic equipment. However, long-wavelength electromagnetic waves are not easily attenuated, due to the limitations of current absorbing materials, including low permeability and a lack of electromagnetic wave loss mechanisms at low frequencies. Herein, we design and prepare one- and two-dimensional Fe0.9Co0.1 nanoalloys with high permeability through an organic templating method combined with a constrained transformation strategy. We systematically investigate the impact of the anisotropy of monodisperse Fe0.9Co0.1 nanoalloys on low-frequency microwave absorption performance. The generous specific surface area of Fe0.9Co0.1 nanosheets facilitate multiple reflections and the scattering of electromagnetic waves within the absorber. This phenomenon, coupled with dielectric resonance, culminates in a maximum reflection loss value of − 48.7 dB at 4.2 GHz. More significantly, Fe0.9Co0.1 nanorods exhibit an absorption intensity of − 35.3 dB at a notably lower frequency of 2.5 GHz, outperforming existing materials, in addition to an efficient absorption bandwidth of 4.2 GHz at a thickness of only 0.7 mm. Through a combination of experimental investigations and finite element simulations, we identify that highly anisotropic magnetic nanorods demonstrate a robust magnetic coupling interaction, substantial interface polarization and quasi-antenna effect. These characteristics result in enhanced low-frequency electromagnetic losses. Our findings indicate that the high anisotropy of the Fe0.9Co0.1 nanoalloys significantly improves their microwave absorption performance, thus emphasizing their substantial potential in the development of efficient low-frequency microwave absorbers.