Space‐time correlation properties of the magnetization process and eddy current losses: Applications. I. Fine wall spacing

摘要

The physical origin of eddy current losses in materials characterized by a very fine and complex domain structure is discussed, on the basis of a general statistical theory of losses developed in preceding papers. It is shown that the same process which is at the basis of the Barkhausen effect, namely the space‐time clustering of elementary domain wall jumps, also gives rise to a detectable dynamic loss contribution in excess to the classical one, in spite of the fact that the ratio between the average wall spacing and the sample thickness is much smaller than unity. A quantitative evaluation of this effect is carried out, obtaining a loss equation which is then compared with some experimental data. Since, according to this interpretation, the same microscopic mechanism is responsible for both the Barkhausen effect and the loss anomaly, it is found that a quantitative relation exists between the parameters of the obtained loss expression and the Barkhausen noise statistical properties. Through this relation, a comparison of loss and Barkhausen noise measurements can provide a valuable test of the consistency of the proposed loss model.