A Possible After‐Effect in Coarse‐Grained MnZn Ferrite of High Permeability

Abstract

AbstractMnZn ferrites of high initial permeability and different grain sizes have been studied. It was found that in materials with coarse grains the permeability and the harmonic distortion increase very rapidly with increasing induction whereas nominally the same materials with fine grains do not show this increase. A “pinning” interaction between ingrown pores and magnetic domain walls appears to be the cause of the rapid increase of permeability and distortion in the coarse grain ferrites. This interaction also causes the real part of the permeability and the maximum of the distortion to drop off at frequencies far below the eddy current cut‐off frequency and the gyromagnetic resonance frequency.