Internal Demagnetizing Factor in Ferrous Metals

Abstract

Modelling the saturation major loop of a ferrous metal produces the intrinsic magnetization parameters; fitting the measured commutation curve, however, can yield different results. The relation of the intrinsic loci of the vertices of the minor loops ( N D = 0 ) to the experimental curve ( N D ≠ 0 ) is investigated. The two-way transformation between the two curves is formulated in closed mathematical form with the help of the internal demagnetization factor, N D . The method is applied to four ferrous metals, with widely different intrinsic properties (soft nonoriented Fe-Si steel, normalized low carbon steel, and Finemet in nanocrystalline and amorphous state) supporting the predictions of the proposal. The developed relationship is model independent and it is shown that the N D factor depends linearly on coercivity based on experimental evidence.