Domain wall size and magnetic losses in frequency spectra of ferrites and garnets

Abstract

It is shown that the value and the frequency of losses in susceptibility spectra follow the relation established by Globus : the value of μ" is proportional to the mean grain size D <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</inf> , the relaxation frequency is proportional to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1/D\min{m}\max{2}</tex> . Curves obtained from series of NiFe <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> O <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf> and YIG samples with various D <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</inf> are reduced to single curves. It has been also possible, by taking into account the specific properties (the spontaneous magnetization, the total and magnetocrystalline anisotropy fields) to reduce the final single curves for both the compositions to a single intercomposition curve of losses as a function of frequency.