One-step hydrothermal synthesis and enhanced microwave absorption properties of Ni_0.5Co_0.5Fe₂O₄/graphene composites in low frequency band

Ni_0.5Co_0.5Fe₂O₄/graphene composites were synthesized successfully via one-step hydrothermal method. The crystal structure, morphology and corresponding elemental distribution, electromagnetic parameters and microwave absorption performances of the as-prepared composites were measured by XRD, SEM, TEM and VNA, respectively. The results indicated that the microwave absorbing performance can be obviously enhanced through the addition of graphene in a suitable range, the magnetic loss plays a dominant contribution for the microwave absorption of composites. The maximum reflection loss of −30.92 dB at 0.84 GHz with a −10 dB bandwidth over the frequency range of 0.58–1.19 GHz is obtained when the composite contains 12 wt% graphene and the thickness of sample is 4 mm. This investigation presents a simple method to prepare Ni_0.5Co_0.5Fe₂O₄/graphene composites with excellent microwave absorption performance in the low frequency band of 0.1–3 GHz.