Effect of Ag substitution on the electromagnetic property and microwave absorption of LaMnO(3)

La(1-x)Ag(x)MnO(3) perovskites with different doping Ag-content were prepared by the sol-gel method. The electromagnetic characteristics and microwave loss behavior of these ion-doped rare-earth manganites were studied in the 2-18 GHz frequency range. The microstructure and morphology of the samples were characterized by X-ray diffraction (XRD), and scanning electron microscopy (SEM) techniques. The complex permittivity spectra, the complex permeability spectra and microwave reflection loss were measured by a microwave vector network analyzer system. The XRD patterns show that the crystalline perovskite main phase ABO(3) is formed and impurity phases disappear when calcined at 1100 degree C, and Ag metal as an impurity phase appears when excessive Ag(+) is doped. The SEM image indicates that many of the La(0.85)Ag(0.15)MnO(3) particles are fiber-like or ellipsoidal. Magnetic loss and dielectric loss coexist and cooperate in microwave attenuation by moderate substitution of Ag(+) for La(3+). The microwave absorption property of the La(0.85)Ag(0.15)MnO(3) sample is enhanced with the bandwidth below -10 dB at about 6 GHz and the peak value of reflection loss is near -25.0 dB at the layer thickness of 2 mm.