High dielectric loss and microwave absorption behavior of multiferroic BiFeO_3 ceramic

摘要

Single-phase multiferroic BiFeO_3 nanoparticles were synthesized by the sol-gel method. Their dielectric properties are investigated in the temperature range of 373-773 K at frequencies 12.4-18 GHz. Multiferroic BiFeO_3 shows high dielectric loss and a strong positive temperature dependence of dielectric properties. The average real and imaginary permittivities of BFO increase from 15.5 and 5.5 to 21.8 and 11.4, respectively. The high dielectric loss below 773 K is ascribed to the defect relaxation loss rather than the leakage current conventionally considered. The calculated attenuation results suggest that BFO nanoparticle is a promising microwave absorber at high temperatures.