High-Magnetization FeCo Nanochains with Ultrathin Interfacial Gaps for Broadband Electromagnetic Wave Absorption at Gigahertz

Abstract

Superparamagnetic FeCo nanochains consisting of assembled ∼25 nm nanoparticles and ∼1 nm gaps are synthesized by facial wet-chemical route and exhibit significant electromagnetic absorption at gigahertz. Both the dielectric and magnetic loss factors present dual-resonance behaviors at 2-18 GHz frequencies, originated from the asymmetric architecture of the cubic FeCo particles that assembled in a one-dimensional chain structure. Theoretical analyses uncover that the origins of the enhancement of electromagnetic losses are ascribed to the high magnetization (228 emu/g) and the ultrathin gaps (∼1 nm), which enhances the Snoek limit and induces anisotropic dielectric polarizations, consequently constructing a proper electromagnetic match.

Spinel zinc ferrite nanoparticles: an active nanocatalyst for microwave irradiated solvent free synthesis of chalcones

“…The same kind of nature was observed in our sample which possesses the moderate saturation magnetization and negligible coercivity/ remanence value. Zhang et al [66] carried out the preparation of FeCo nano-chains made up of assembly having nanoparticles with approximately 1 nm gap and studied their electro-magnetic absorption properties in the GHz range. The superparamagnetism was also observed in this report which is analogous to the magnetic behaviour of present sample as the size of zinc ferrite nanoparticles is smaller than the superparamagnetic critical dimension.…”

Metal‐Organic Framework Derived Hierarchical Co/C@V2O3 Hollow Spheres as a Thin, Lightweight, and High‐Efficiency Electromagnetic Wave Absorber

“…[11] This indicates that V 2 O 3 may be ap romising EM wave absorber, due to its superior dielectric loss compared with that of general oxidess uch as Fe 2 O 3 ,C o 3 O 4 ,C oO, NiO, and TiO 2 . However,t ot he best of our knowledge,r esearch on the EM wave absorption performance of V 2 O 3 has been scarceu ntil now.R ecently,m aterials with designed morphologies, such as laminated, [12] flower-like, [13] catenulate, [14] porous, [15] and hollow nanostructures [16] have attracted considerable attention for improveda bsorption performance with reduced density.A mong them, hollow-structuredm aterials stand out due to the high specific area and significantly reduced density,w hich can also induce multiple reflections between the pores for enhanced absorption. [17] Based on these benefits, V 2 O 3 with au nique hollow feature may be ad esirable EM wave absorber with both strong absorption capacity and low density.…”

Excellent Electromagnetic Wave Absorption of Iron‐Containing SiBCN Ceramics at 1158 K High‐Temperature

“…In this field, metamaterials, ferrites, carbon family materials (carbon black, carbon fibers (CFs), carbon nanotubes (CNTs), graphite flakes, graphene foams, or graphenes), metal‐carbon nano‐hybrids (Fe 3 O 4 /CNTs/CFs, Fe 3 O 4 /graphene capsules, Co‐carbon nanotubes‐graphene, Co‐Carbon metal‐organic framework), core/shell hierarchical nanostructures and dielectronic ceramics, 2D transition metal carbides (MXenes) show favorable EM absorbing performance in ambient environment . However, at high temperature more than 873 K (600 °C), most of ferrites are limited by low Curie temperature ( T c ), for example, 360–440 °C for Ba 3 Me 2 Fe 24 O 41 (Me = Co, Cu, Ni) and 570 °C for Ni‐Zn ferrites .…”