【摘要】 用溶胶凝胶法制备La0.8Sr0.2Mn1-yFeyO3(y=0.10,0.12,0.14,0.16)样品,测试并分析该样品在2~18 GHz微波频率范围的复介电常数、复磁导率、损耗角正切及微波吸收系数与频率的关系,发现y=0.12,0.14时吸波的效果最好。样品厚度为2 mm、y为0.12时,有2个吸收峰,吸收峰值最高达22 dB,10 dB以上吸收频带宽度达6.2 GHz;厚度2.21 mm样品8 dB以上的吸收频宽达8.5 GHz。初步探讨了该材料的电磁损耗机理,电磁特性参数在频率为12.4 GHz位置发生阶跃式变化,在小于12.4 GHz频率范围以介电损耗为主,在大于12.4 GHz频率范围以磁损耗为主,这与Fe对Mn3+—O—Mn4+之间的影响有关。电导率测试表明在室温范围内电导在半导体范围内,有利于降低微波在氧化物表面的反射率。更多还原

【Abstract】 The experiment samples of La_0.8Sr_0.2Mn_1-yFe_yO₃（y=0.10,0.12,0.14,0.16） were prepared by sol-gel process,and those complex dielectric constant,complex permeability,loss tangent and absorption coefficient in 218GHz microwave frequencies were measured and analyzed.The absorption mechanism of the material was studied generally.The result shows that when the thickness of the sample is 2mm and y=0.12 there are two absorption peaks;the highest is 22dB and the effective band width of more than 10dB reaches 6.2GHz.The band width of more than 8dB of the sample with thickness of 2.21mm attaines 8.5GHz.The electromagnetic loss parameter increases or decreases suddenly at frequency about（12.4）GHz,when the frequency is less than（12.4）GHz,the dielectric loss is the major loss.When the frequency is more than 12.4GHz,the magnetic loss is the major loss.It shows to be semiconductor at room temperature by testing the conductance,which is beneficial to reducing the reflect of microwave.更多还原