Characterization of grain boundary conductivity of spin-sprayed ferrites using scanning microwave microscope

J. Myers, T. Nicodemus, Y. Zhuang, T. Watanabe, N. Matsushita, M. Yamaguchi

Research output: Contribution to journalArticlepeer-review

Abstract

Grain boundary electrical conductivity of ferrite materials has been characterized using scanning microwave microscope. Structural, electrical, and magnetic properties of Fe3O4 spin-sprayed thin films onto glass substrates for different length of growth times were investigated using a scanning microwave microscope, an atomic force microscope, a four-point probe measurement, and a made in house transmission line based magnetic permeameter. The real part of the magnetic permeability shows almost constant between 10 and 300MHz. As the Fe3O4 film thickness increases, the grain size becomes larger, leading to a higher DC conductivity. However, the loss in the Fe3O4 films at high frequency does not increase correspondingly. By measuring the reflection coefficient s11 from the scanning microwave microscope, it turns out that the grain boundaries of the Fe3O4 films exhibit higher electric conductivity than the grains, which contributes loss at radio frequencies. This result will provide guidance for further improvement of low loss ferrite materials for high frequency applications.
Original languageEnglish
Article number17A506
JournalJournal of Applied Physics
Volume115
Issue number17
DOIs
StatePublished - May 7 2014
Event55th Annual Conference on Magnetism and Magnetic Materials - Atlanta, United States
Duration: Nov 14 2010Nov 18 2010
Conference number: 55

ASJC Scopus Subject Areas

  • General Physics and Astronomy

Keywords

  • Electromagnetism
  • Electrical conductivity
  • Microwave frequencies
  • Glass
  • Crystallographic defects
  • Dielectric properties
  • Ferromagnetic materials
  • Atomic force microscopy
  • Resistivity measurements
  • Thin films

Disciplines

  • Electrical and Computer Engineering

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