Flower-like hierarchical Fe3O4-based heterostructured microspheres enabling superior electromagnetic wave absorption.

[Display omitted] • A hierarchical heterostructure is fabricated by incorporating the TiO 2 or SiO 2 into the Fe 3 O 4 micro-flower framework. • Adjusting the content of TiO 2 and SiO 2 can effectively regulate the impedance matching. • An extremely broad effective absorption of 7.3 GHz can be achieved at a single thickness of only 2.0 mm for Fe 3 O 4 /TiO 2. Rational design of hierarchical heterogeneous structured Fe 3 O 4 toward boosted electromagnetic wave absorption (EMA) is extremely imperative and needs further exploration. In this study, we use two types of dielectric components, including TiO 2 and SiO 2 particles, as intercalations anchor in Fe 3 O 4 micro-flower framework through a sol–gel process to construct hierarchical hetero-structures. The tunable contents of anchoring particles allow the composites to retain their micro-flower structure and enable a reinforced polarization loss as well as enhanced impedance matching. As a result, both Fe 3 O 4 /TiO 2 and Fe 3 O 4 /SiO 2 exhibit excellent EMA performance. In detail, the Ti-2 possesses an effective absorption bandwidth (EAB) of 7.3 GHz (9.3–16.6 GHz) at 2.0 mm and a reflection loss (RL) of −67.1 dB at 3.78 mm. Si-2 exhibits a strong absorption with RL of −59.1 dB at 2.35 mm and an EAB of 4.8 GHz (8.3–13.1 GHz) at 2.0 mm. More importantly, an in-depth analysis confirms that the EMA of Ti-2 is superior to the previously reported results in terms of EAB, matching thickness, and absorption intensity. Therefore, this work provides a novel pathway to fabricate high-performance EMA absorbers via rational design of hierarchical hetero-structure. [ABSTRACT FROM AUTHOR]