Microwave absorption studies of nanocrystalline prepared by the citrate sol–gel method

Electromagnetic wave absorption properties were investigated in the Mn–Ti–Sn substituted strontium M-type hexagonal ferrites (SrMnx/2(TiSn)x/4Fe12−xO19) prepared by the citrate sol–gel method. The crystalline structure, size, coercivity and microwave absorption properties of the particles were investigated by means of X-ray diffraction, transmission electron microscopy (TEM), vibrating sample magnetometry and a vector network analyzer. Results showed that the materials have hexagonal structures with high purity. Based on microwave measurements on reflectivity, SrMnx/2(TiSn)x/4Fe12−xO19 may be a good candidate for electromagnetic compatibility and other practical applications at high frequency. A wide bandwidth of microwave absorption is obtained in the composite samples containing ferrite powders with composition x = 2 and x = 3 in X-band frequencies. A minimum reflection loss of −39 dB was observed at 9.7 GHz for a sample of x = 3 . It should be noted that thicknesses of the absorbers are only 1.6 mm.