Tunable complex permeability and enhanced microwave absorption properties of BaNixCo1−xTiFe10O19

In order to achieve a broader absorption bandwidth with smaller reflection loss (RL) in electromagnetic absorber, nickel ions (Ni 2+ ) were employed to partially occupy the sites of cobalt ions (Co 2+ ) in BaCoTiFe 10 O 19 . Ni-doped barium hexaferrite (BaNi x Co 1 − x TiFe 10 O 19 ) powders were synthesized via the sol–gel combustion method. Subsequently, the microwave absorbing composites were prepared by mixing the BaNi x Co 1 − x TiFe 10 O 19 powders with the paraffin. As the doped Ni 2+ ions were in augment, the grain size of BaNi x Co 1 − x TiFe 10 O 19 decreased from 400   nm to 50   nm. Based on the electromagnetic parameters measured by the vector net-analyzer in the frequency of 0.5–18   GHz, it was found that the peaks of the complex permeability shifted to the high frequency region with the increase of the doped Ni. Moreover, the composite ( x   =   0.4) possessed a maximum reflection loss (RL) of −47.49   dB at 13.28   GHz with a matching thickness of 2.0   mm. It also had a bandwidth below −20   dB ranging from 12.36   GHz to 18   GHz, which has great potentials applications in the high frequency fields of the microwave absorbing materials.