Synthesis, electromagnetic and microwave absorption properties of Ba3Co2Fe24O41 hexaferrites for GHz application

Ba3Co2Fe24O41 Z-type hexaferrite has been prepared by the citric acid sol-gel method, and the structural and electromagnetic properties have been investigated in detail. The results showed that almost single-phase Z-type hexaferrites were obtained by a double calcination process. The maximum saturation magnetization of 41.7 emu/g and minimum coercivity of 19.8 Oe were obtained for the sample first calcined at 1300 degrees C and second calcined at 1315 degrees C, respectively. And a high resonance frequency f(r) = 3.16 GHz and large permeability mu' = 3.36 at 100 MHz have been achieved. The calculated frequency dependence spectrum of the reflection loss (RL) showed a largest absorbing value approaching 50 dB at 4.1 GHz for the sample with a thickness of 5 nun, which was first calcined at 1250 degrees C and second calcined at 1315 degrees C, respectively. Furthermore, as for the sample first calcined at 1300 degrees C and second calcined at 1315 degrees C with a thinner thickness of 3 mm, the RL value was almost -30 dB at 9.7 GHz, which was greatly appropriate for the high-frequency devices applications.