Strong and wide microwave absorption of SrFe12-2xNixRuxO19 enhanced by dislocation stripes

SrFe12-2xNixRuxO19 become promising microwave absorbing materials at 0.1-18GHz with Ni and Ru doping. Regular lattice dislocation stripes are observed in high-resolution transmission electron microscopy images of x=0.5 and 0.7. The observed strong microwave absorption is mainly contributed by natural magnetic resonance, which is widened by local magnetic fields at dislocation stripes. At dislocation stripes, interface polarization also forms. Both the x=0.5 and 0.7 samples are excellent single-layer microwave absorbers. In x=0.5, the bandwidth of reflection loss (RL) < -10dB is broader than 11.31GHz of 6.69GHz to >18GHz. In x=0.7, an ultra-low RL = -82dB is observed with a fairly wide bandwidth (RL < -10dB) of over 8.8GHz in the range of 9.2GHz to >18GHz. As the thickness and the doping content vary, the absorption is able to cover the full range of 3.5-18GHz. The excellent microwave absorption is based on the collaboration of good impedance matching and high attenuation factor. The quarter-wavelength criteria explain the relationship between the optimum thickness and the frequency. Compared to the advanced materials reported, both the absorption strength and the bandwidth of SrFe12-2xNixRuxO19 are very competitive. Published under license by AIP Publishing.