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

Grain boundary electrical conductivity of ferrite materials has been characterized using scanning microwave microscope. Structural, electrical, and magnetic properties of Fe{sub 3}O{sub 4} 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 300 MHz. As the Fe{sub 3}O{sub 4} film thickness increases, the grain size becomes larger, leading to a higher DC conductivity. However, the loss in the Fe{sub 3}O{sub 4} films at high frequency does not increase correspondingly. By measuring the reflection coefficient s{sub 11} from the scanning microwave microscope, it turns out that the grain boundaries of the Fe{sub 3}O{sub 4} 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.
Authors:
; ;  [1] ; ;  [2] ;  [3]
  1. Department of Electrical Engineering, Wright State University, Dayton, Ohio 45435 (United States)
  2. Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama (Japan)
  3. Department of Electrical Engineering, Tohoku University, Sendai 980-8579 (Japan)
Publication Date:
OSTI Identifier:
22273910
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 17; Conference: 55. annual conference on magnetism and magnetic materials, Atlanta, GA (United States), 14-18 Nov 2010; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ATOMIC FORCE MICROSCOPY; ELECTRIC CONDUCTIVITY; FERRITES; GLASS; GRAIN BOUNDARIES; GRAIN SIZE; IRON OXIDES; MAGNETIC SUSCEPTIBILITY; MICROWAVE RADIATION; RADIOWAVE RADIATION; REFLECTION; SPIN; SUBSTRATES; THIN FILMS