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Complex Permeability Measurements of Microwave Ferrites1

Published online by Cambridge University Press:  10 February 2011

Richard G. Geyer  and
Jerzy Krupka
Richard G. Geyer
Affiliation:
Electromagnetic Fields Division, National Institute of Standards and Technology, MS 813.08, Boulder, CO 80303–3328, [email protected]
Jerzy Krupka
Affiliation:
Instytut Mikroelektroniki i Optoelektroniki Politechniki Warszawskiej, Warszawa, Poland
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Abstract

A rigorous and accurate method for the experimental determination of the complex permeability of demagnetized ferrites at microwave frequencies is presented. The measurement uses low- loss dielectric ring resonators, is nondestructive, and allows complex permeability characterization of a single ferrite sample to be performed at frequencies from 2 GHz to 25 GHz. A wide variety of ceramic microwave ferrites having various compositions and differing saturation magnetizations were measured in the demagnetized state. Generally, at any frequency greater than gyromagnetic resonance, the real part of the complex permeability increases as saturation magnetization increases.For the same frequency magnetic losses increases as saturation magnetization increases. The real permeability results are compared with magnetostatic theoretical predictions. Measurement data show excellent agreement with theoretical predictions, but only when 2πγMs/ω < 0.75, where γ is the gyromagnetic ratio, Ms is saturation magnetization, and ω is the radian rf frequency.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 430: Symposium O – Microwave Processing of Materials V , 1996 , 257
Copyright
Copyright © Materials Research Society 1996

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References

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