Effect of sintering temperature on the structural, dielectric and magnetic properties of Ni0.4Zn0.2Mn0.4Fe2O4 potential for radar absorbing

K. Praveena, K. Sadhana, S. Matteppanavar, Hsiang Lin Liu

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)

Abstract

Ni0.4Zn0.2Mn0.4Fe2O4 nanopowders were prepared by sol-gel auto-combustion method, densified at different temperatures 400–700 °C/4 h using conventional sintering method. The grain sizes of all the samples vary between 18 nm and 30 nm. The hysteresis loops show high saturation magnetization and low coercivity, indicating magnetically soft behaviour of the material. The real and imaginary parts of permittivity is almost constant upto 1 GHz and increases with further increase of frequency. The permeability is ruled by Snoek's law, the values of μ′ increases with increase of temperature and the resonance frequency increases with an increase of temperature. The reflection coefficient is however increasing with sintering temperature and the maximum loss is observed in the range of 100 MHz–1 GHz. Sample sintered at 700 °C has shown maximum reflection loss and this loss occurs due to absorption, destructive interference and multiple internal reflections in the sample. Quality factor is constant upto 380 MHz and increases with frequency for all the samples sintered at different temperatures. The TC for all the samples is above ~230 °C. The room temperature EPR spectra confirm the oxidation state of Fe3+. The g-factor is in the range of ~2.

Original languageEnglish
Pages (from-to)343-352
Number of pages10
JournalJournal of Magnetism and Magnetic Materials
Volume423
DOIs
Publication statusPublished - 2017 Feb 1

Keywords

  • Electron microscopy
  • Electronic paramagnetic resonance (EPR)
  • Impedance spectroscopy
  • Magnetic materials
  • Sol-gel chemistry

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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