Large-scale controlled synthesis of magnetic FeCo alloy with different morphologies and their high performance of electromagnetic wave absorption

Magnetic materials of FeCo alloy with different morphologies (nanocube, nanoplate and flower-like structure) have been synthesized by controlling the molar ratio of Fe²⁺ to Co²⁺, concentrations of cyclohexane and PEG-400. The structure and morphology were characterized by several analytical techniques, including XRD, SEM, TEM, XPS and VSM. The microwave-absorbing properties were measured by a vector network analyzer. The SEM and TEM photographs reveal that the edge length of FeCo nanocube is about 215 nm, the diameter and thickness of the nanoplate is 100 and 15 nm, respectively. The average diameter of flower-like FeCo is about 1.5 μm. The investigation of the electromagnetic wave absorbability revealed that flower-like FeCo exhibited excellent electromagnetic wave absorption properties compared with FeCo nanocube and FeCo nanoplate due to the special structure. The maximum reflection loss of flower-like FeCo was up to −43 dB at 13.1 GHz and the absorption bandwidth with the reflection loss below −10 dB was 5.8 GHz (from 2.7 to 5.4 GHz and from 12 to 15.1 GHz) with a thickness of 3.4 mm. Furthermore, this work offers a simple solvothermal route to fabricate shape and size-controlled FeCo alloy, which can be used as an attractive candidate for new type of electromagnetic wave absorbers.