Journal of South China University of Technology (Natural Science Edition) ›› 2009, Vol. 37 ›› Issue (3): 43-46.

• Materials Science & Technology • Previous Articles     Next Articles

Microwave-Absorbing Properties of La0. 8 Sr0. 2 Mn0. 86 Fe0. 14-x CoxO3

Bei Cheng-xun1  Wang Da1  Yao Ruo-he2  Li Bin2   

  1. 1. Physics Teaching and Experiment Center of South Campus, South China University of Technology, Guangzhou 510006, Guangdong, China; 2. School of Electronic and Information Engineering, South China University of Technology, Guangzhou 510640, Guangdong, China
  • Received:2008-04-24 Revised:2008-06-03 Online:2009-03-25 Published:2009-03-25
  • Contact: 贝承训（1955-），男，高级实验师，主要从事功能材料的研究． E-mail:wangda@scut．edu．cn
  • About author:贝承训（1955-），男，高级实验师，主要从事功能材料的研究

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Abstract:

La0.8Sr0.2Mn0.86Fe0.14-xCoxO3（ X = O. 01, 0. 02, 0. 03 ） crystal powders were synthesized via the sol-gel method, and the crystal structure of the product was characterized by means of XRD. Then, the complex permittivity and permeability of the product in the frequency range of 2 - 18 GHz were measured using a microwave vector network analyzer. Moreover, the curves describing the relationship between the microwave reflectivity and the frequency were obtained according to the measured data. The results show that, with a thickness of 1.80 mm, La0.8Sr0.2Mn0.86Fe0.13Co0.01O3 is of an absorption peak height of 27. 9 dB and an absorption bandwidth in 2 -18 GHz of 5.3 GHz, while with a thickness of 2.00mm, the height decreases to 26dB and the bandwidth to 4. 9GHz. According to the tangents of both electric loss and magnetic loss angles, the microwave absorption attributes to both the dielectric and the magnetic loss, especially the former. It is also indicated that the doping of Fe and Co changes the double-exchange of Mn^3＋--O--Mn^4＋ system and the electromagnetic parameters of the material, thus improving the microwave-absorbing properties.

Key words: microwave-absorbing material, LaMnO3 doping, complex permittivity, complex permeability