Rational design of lightweight microwave absorbers: synergistic dielectric-magnetic loss in 3D hierarchical graphene/Fe ₃ O ₄ microflower composites

A hierarchical RGO/Fe ₃ O ₄ microflower composite is developed as a lightweight microwave absorber, achieving a minimum reflection loss of −63.2 dB and an effective absorption bandwidth of 6.89 GHz at an ultralow filler loading of only 8 wt%.