Microwave Absorption Properties of Monovalent Doped La<sub>0.85</sub>Ag<sub>0.15</sub>MnO<sub>3</sub> Manganites Prepared by Solid State Method

Abstract

The microwave absorption properties of La0.85Ag0.15MnO3 prepared by solid state method was investigated. Analysis of X-ray diffraction data using a refinement technique confirmed the rhombohedral structure of the samples. The microstructure of the sample characterised from field emission scanning electron microscope micrographs showed irregular grain shapes with grain sizes ranging from 800 to 1500 nm. M-H curves revealed the weak ferromagnetic properties of the sample at room temperature. The real and imaginary parts of permittivity and permeability as well as microwave reflection loss were measured by a vector network analyser in the 8–18 GHz frequency range. The La0.85Ag0.15MnO3 sample showed a minimum reflection loss of –57.2 dB at 16.41 GHz, with a –10dB bandwidth (corresponding to reflection loss below –10 dB, or 90% absorption) of 2.67 GHz. The microwave absorption of La­­­­0.85Ag0.15MnO3 mainly arises from the conduction loss and domain wall motion which contributed to dielectric loss and magnetic loss, respectively.