Controlled synthesis of PPy/Ba<sub>0.9</sub>Nd<sub>0.1</sub>Fe<sub>11.5</sub>Cr<sub>0.5</sub>O<sub>19</sub> composites and its electrical-magnetic property

Abstract

Nd-doped Ba ferrite powders (Ba1-xNdxFe11.5Cr0.5O19,x=0.00,0.05,0.10,0.15,0.20) were obtained by a sol-gel method,and Ba0.9Nd0.1Fe11.5Cr0.5O19 with good magnetic property was chosen as magnetic core to prepare polypyrrole/Ba0.9Nd0.1Fe11.5Cr0.5O19 ((PPy/BNFCO) composites with different ferrite contents by in situ polymerization method. The structures,morphology,electromagnetic property of ferrite powders and composites were characterized by powder X-ray diffractometer (XRD),transmission electron microscope (TEM),scanning electron microscope (SEM),Fourier transform infrared (FTIR) spectra,four-probe instrument,vibrating sample magnetometer (VSM) and vector network analyzer. It was found that Nd contents markedly affected the magnetic properties of Ba1?xNdxFe11.5Cr0.5O19 ferrites. The results also indicated that the PPy/BNFCO composites had obvious core-shell structure. The saturation magnetization of composites increases with increasing of BNFCO content,electrical conductivity is directly proportionalto the PPy content,and the seepage threshold of the composite system locate in mPy/mBNFCO equal to 5/1. The reflection loss of composites and the effective bandwidth for electromagnetic wave were attributed to the synergistic effect between PPy anf BNFCO. The PPy/BNFCO composites with mPy/ mBNFCO = 5/1 have a maximum synergy between its components,show a maximum reflection loss of -27.68 dB at 13.9 GHz and an available bandwidth of 9.04 GHz. It was suggested the PPy/BNFCO composites can be used as a advancing absorption and shielding materials for electromagnetic wave due to their favorable microwave absorption properties.