Facile synthesis of rGO/SmFe 5 O 12 /CoFe 2 O 4 ternary nanocomposites: Composition control for superior broadband microwave absorption performance

•rGO/Sm3Fe5O12/CoFe2O4 composites are fabricated by a hydrothermal process.•Introducing CoFe2O4 and rGO into Sm3Fe5O12 can tune dielectric and magnetic loss.•RL reaches −73.71 dB at 14.88 GHz with a thickness of 2.09 mm.•The effective bandwidth (RL < −10 dB) is 7.12 GHz.