Electromagnetic Properties of Lai1-xSrxMnO3 Prepared by Sol-Gel Method

Lai(1-x)Sr(x)MnO(3) (x=0, 0.1, 0.2, 0.3) nanometer powders were prepared by sol-gel method. The crystal structure, magnetic properties, electromagnetic properties and microwave absorption properties of LSMO with different doping amounts of Sr2+ were investigated. The results show that with the increase of the amount of Sr2+, the lattice constant and Mn-O-Mn bond angle increase, while the average grain size decreases gradually and the complex dielectric constant increases first and then decreases. The LSMO changes from antiferromagnetism to ferromagnetism when Sr2+ is doped. In the range of 2 similar to 18 GHz, the best absorbing properties can be arrived when the doping amount of Sr2+ is 0 and the thickness is 2 mm. The effective frequency band corresponding to the reflectivity less than -10 dB is 12.5 similar to 18 GHz and the effective bandwidth reaches 5.5 GHz. The doping of Sr2+ can make the absorbing bandwidth move to the low frequency availably. In the X-band, the effective bandwidth of the LSMO reaches 2.6 GHz when the doping amount of Sr2+ is 0.2 and the thickness is 2.3 mm. It is proved that LSMO is a kind of dielectric loss absorbing material with excellent performance.