Full X-Ku band microwave absorption by Fe(Mn)/Mn7C3/C core/shell/shell structured nanocapsules

Xianguo Liu, Siu Wing Or, Siu Lau Ho, Chi Chuen Cheung, Chung Ming Leung, Zheng Han, Dianyu Geng, Zhidong Zhang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

46 Citations (Scopus)


New type of Fe(Mn)/Mn7C3/graphite nanocapsules was prepared by a modified arc discharge technique in ethanol vapor, with Fe(Mn) solid solution nanoparticles as the core, Mn7C3as the inner shell, and graphite as the outer shell. The Cole-Cole semicircle approach was adopted to explain the ternary dielectric resonance, due to a cooperative consequence of the core/shell/shell interfaces and the dielectric Mn7C3and C shells. A remarkable increase in the anisotropy energy led to a shift in the natural resonance frequency to 6.6 GHz. Dielectric losses come from the ternary dielectric resonance while magnetic losses were from the magnetic natural resonance. An optimal reflection loss (RL) of -142.1 dB was observed at 12 GHz for 5.0 mm thickness layer. RL exceeding -10 dB was obtained at 6.6-18 GHz for 1.4 mm thickness, covering the whole X band (8-12 GHz), Ku band (12-18 GHz), and some of C band (6.6-8.0 GHz). RL exceeding -20 dB was found at 6-10.6 GHz for 2.2 mm thickness.
Original languageEnglish
Pages (from-to)9071-9075
Number of pages5
JournalJournal of Alloys and Compounds
Issue number37
Publication statusPublished - 15 Sep 2011


  • Carbon
  • Complex permeability
  • Complex permittivity
  • Electromagnetic wave absorption
  • Nanocapsules
  • Reflection loss

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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