Dielectric permittivity and microwave absorption properties of transition metal Ni and Mn doped SiC nanowires

In order to enhance the microwave absorption properties of SiC nanowires, two transition metals Ni and Mn were selected as doping elements to improve their electromagnetic parameters. The experimental results indicate that Ni and Mn as catalysts reduce the stacking defect density of SiC nanowires, which will weaken the interfacial polarization loss induced by stacking defects. However, they can increase the electrical conductivity of SiC nanowires and generate new impurity defects, thereby effectively improving the conductance loss and dipole polarization loss. Therefore, the dielectric loss of SiC nanowires is significantly enhanced, but they still do not have considerable magnetic loss capability. In addition, Ni and Mn doping also improves the impedance matching characteristics of SiC nanowires. Therefore, the microwave absorption ability of SiC nanowires is effectively enhanced. As the nanowire filling ratio is 20 wt%, the minimum reflection loss of the Ni0.01Si0.99C nanowire is -11.1 dB and the effective absorption bandwidth is 1.1 GHz (9.3-12.4 GHz) at a thickness of 2.8 mm; Mn0.01Si0.99C nanowires have a minimum reflection loss of -16.8 dB and an effective absorption bandwidth of 3.1 GHz (9.3-12.4 GHz) at a thickness of 2.8 mm.