The Study On Microwave Absorption Performances Of Zn-Co-Ti Doped BaM/C/Co Composite

The doped BaM,Co/C composites,BaZn0.2Co0.8TiFe10O19/Co/C composites have been studied on the wave absorption performance and the similar Cole-Cole semicircles in ?"-?' curves.For the doped BaM,the variation of coercivity(Hc)and saturation magnetization(Ms)will affect the static permeability(?'0),which can affect the width of the absorption band.For Zn2+,Ni2+ and Co2+ occupied different oxygen vacancies in BaM,the doped BaM absorbing materials can be obtained with small Hc and big Ms.BaZn0.2Co0.8TiFe10O19 has the best comprehensive absorption perfomance in the doped BaM.Its absorption band of RL<-10 dB is close to 7 GHz(10.47-17.47 GHz),and the absorption band of RL?-20 dB is about 4.63 GHz(11.70-16.33 GHz).The Co/C composite was successfully prepared by solvothermal method.Due to the reaction temperature being about 180?,Co2+ have been successfully reduced to the hexagonal close-packed Co.There have some defects of C,which is benefit to dielectric loss.When d=1.9 mm,the minimum RL of S5-1 is-47.50 dB.When d=1.9 mm,the RL?-10 dB absorption band of S5-3 is 5.6 GHz.Based on the good absorption perfomance of BaZn0.2Co0.8TiFe10O19 and S5-3,the BaZn0.2Co0.8TiFe10O19/Co/C composites have been successfully prepared by the two step methods of sole-gel and solvothermal.When d=1.9 mm,the minimum RL of S6-1 reached-47.23 dB at 9.95 GHz.When d=1.9 mm,the RL?-10 dB absorption band of S6-4 reaches 6.82 GHz(11-17.82 GHz).Based on the Cole-Cole semicircle of ?"-?' curves,the similar Cole-Cole semicircles have been discussed in ?"-?' curves.By using the magnetic field intensity and magnetic induction intensity of alternating magnetic field,magnetic ring around the wire and its equivalent circuit and Landau-Lifshitz-Gilbert equation,the existence of similar Cole-Cole semicircles have been proved.What's more,the similar Cole-Cole semicircles is related to the damping coefficient of materials,the frequency of the electromagnetic wave,the resonance frequency and the intensity of the resonance peak.Each similar Cole-Cole semicircle corresponds to a resonance loss.We conclude that the first similar Cole-Cole semicircles has the greatest impact on the magnetic loss,namely,the its extremum and the complete and smooth of the semicircle will affect the magnetic loss.For the absorbing materials mainly from magnetic loss,the first similar Cole-Cole semicircles has great impact on absorbing performance.