Microwave absorbing characteristics of LAMO/Ni_2Z composite powders prepared by sol-gel precursor method

Composites of La0.85Ag0.15MnO3 with perovskite structure and Z-type ferrite(Ba0.7Sr0.3)3Ni2Fe24O41 were synthesized by the sol-gel precursor calcination method. Microstructure and morphology of the composites were analyzed by X-ray diffraction meter(XRD) and scanning electron microscope(SEM). Electromagnetic parameters and microwave absorption of the composites were measured by the microwave vector network analyzer system. The main influencing factors and their function mechanism on microwave absorbing for the composites were also explored. The results show that, the microwave absorption peak value is-30 dB and the bandwidth below-10 dB reaches 3.9 GHz in 2-18 GHz frequency range for the composite with 40wt% La0.85Ag0.15MnO3 prepared by calcination temperature of 1 250 ℃, which is much better than those of the single phase materials. Because of coexistence of dielectric loss and magnetic loss, interfacial and magnetoelectric coupling effect for the composite, the permittivity can be regulated and controlled effectively and impedance matching as well as microwave absorption are improved.