纳米La_(0.8)Ba_(0.2)MnO_3/Ni粉复合体系的微波吸收性能  

Microwave absorbing properties of La_(0.8)Ba_(0.2)MnO_3/Ni/nickel nano-composite system

作　　者：周克省[1] 邓建杰[1] 尹荔松[1] 马诗宏[1] 高松华[1] 

机构地区：[1]中南大学物理科学与技术学院,湖南长沙410083

出　　处：《中南大学学报（自然科学版）》2008年第1期98-102,共5页Journal of Central South University:Science and Technology

基　　金：湖南省科技计划资助项目(05JT1034)

摘　　要：采用溶胶-凝胶法制备La0.8Ba0.2MnO3粉体,并与纳米Ni粉按不同质量比复合,制得复合材料样品。测量样品在2～18 GHz频率范围内的复介电常数、复磁导率并计算微波反射系数,分析不同组分对材料微波吸收性能的影响及其可能的吸收机制。研究结果表明:复合体系比单一组分样品具有更好的吸收效果;当La0.8Ba0.2MnO3含量为62.5%时,材料微波吸收效果最佳;当样品厚度为2 mm时,大于10 dB的吸收频宽达到3.6 GHz,最大吸收峰值为24 dB;当样品厚度为1.8 mm时,大于10 dB的吸收频宽达到3.3 GHz,最大吸收峰值为44 dB;LaMnO3在A位掺杂Ba2+,其电磁性能将发生变化,再与磁性纳米Ni粉复合,介电损耗和磁损耗的综合作用能使体系的微波吸收效能显著加强。La0.8Ba0.2MnO3 powders were synthesized by sol-gel process and the La0.8Ba0.2MnO3/nickel composite samples were prepared by compounding Lao.sBao.EMnO3 powders and nickel nano-particles with different mass ratios, The permittivity and permeability of complex were measured in the frequency range of 2-18 GHz and the reflection coefficient was calculated according to the measured data, The microwave absorbing properties and absorbing mechanism of these samples were studied. The result shows that the microwave absorbing effect of the composite samples is better than that of the single component, When the mass fraction of La0.8Ba0.2MnO3 is 62.5%, these samples have the best absorption; when the bandwidth is higher than 10 dB it is 3,6 GHz and the peak is 24 dB at the thickness of 2 mm but 3.3 GHz and 44 dB at 1.8 mm, The electromagnetic properties will change when LaMnO3 is doped by Ba2＋ at site A and then La0.8Ba0.2MnO3 is compounded with nickel nano-powders which have magnetic property, so that the microwave absorption of the composite system is enhanced greatly because of a common effect of dielectric loss and magnetic loss.

关 键 词：微波吸收 La0.8Ba0.2MnO3 Ni 纳米复合材料 介电损耗 磁损耗 

分 类 号：O441.6[理学—电磁学]