La_(0.6)Ce_(0.4)Mn_(1-y)Fe_yO_3微波吸收特性

Properties of La_(0.6)Ce_(0.4)Mn_(1-y)Fe_yO_3 in Absorbing Microwave

用溶胶-凝胶法制备了La0.6Ce0.4Mn1-yFeyO3（y=0.00,0.12,0.14,0.16,0.18）样品。用微波矢量网络分析仪测试了该样品在2-18 GHz微波频率范围的复介电常数、复磁导率,根据测量数据计算了电磁损耗角正切及微波反射率与频率的关系。结果表明,当B位掺入铁元素时,样品吸收峰值增大,有效吸收频带增宽,在y=0.14时,样品微波吸收效果最好。当样品厚度为2.00 mm,y=0.14时,吸收峰值为38dB,10 dB以上频带宽度达4.1 GHz。初步探讨了该材料的电磁损耗机理,发现损耗吸收来自磁损耗和介电损耗的共同作用,吸收峰所在频率介于介电损耗角正切最大值与磁损耗角正切最大值对应的频率之间,即在12.7 GHz附近。对样品的电阻率测试表明,其室温范围内电导在半导体范围内,有利于降低微波在样品表面的反射率。

The samples of La0.6 Ce0.4 Mn1-yFeyO3 （y = 0.12, 0.14, 0.16, 0.18） were prepared by sol-gel process, and their complex dielectric constant and permeability were measured in the frequency range of 2-18 GHz by microwave vector network analyzer. The relation between the reflectance （R） and frequency （f）, and between the loss tangent and frequency were calculated from the measured data. The result showed that the absorption peaks of the samples were increased and the effective absorption band was broadened when Fe was incorporated, and there was the best effect of microwave absorption for the sample of y = 0.14. When the thickness of the mm and y = 0.14, the highest absorp sample was 2.00 tion peak was 38 dB and the effective band width larger than 10 dB reached 4. 1 GHz. The electromagnetic loss mechanism of the material was studied generally. Both the effect of dielectric loss and magnetic loss resulted in the microwave absorption. The frequency of absorption peak was about 12.7 GHz between the frequency of maximums of dielectric and magnetic loss tangent. The material＇s resistivity at room temperature was in range of semiconductor by measurement, which was important to reduce microwave reflectivity of the material.