Bandwidth Enhancement in Microwave Absorption of Binary Nanocomposite Ferrites Hollow Microfibers

摘要

The binary Ba_(0.5)Sr_(0.5)Fe_(12)O_(19) (BSFO)/Ni_(0.5)Zn_(0.5)Fe_2O_4 (NZFO) nanocomposite ferrites hollow microfibers with high aspect ratios have been prepared by the gel precursor transformation process. These microfibers possess a high specific surface area about 45.2 m~2 g~(-1), and a ratio of the hollow diameter to the fiber diameter estimated about 5/7. The binary nanocomposite ferrites are formed after the precursor calcined at 750℃ for 3 h. Their minimum reflection loss (RL) is -38.1 dB at 10.4 GHz. The microwave absorption bandwidth with RL value exceeding -20 dB covers the whole X-band (8.2-12.4 GHz) and Ku-band (12.4-18 GHz). This enhancement in microwave absorption can be attributed to the exchange-coupling interaction, interfacial polarization and small size effect in nanocomposite hollow microfibers.