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Figure 18. Micromagnetic results for remanence and coercivity for different soft-hard magnets with different grain sizes. (Courtesy of T. Schrefl).

Rave et al. [127], and T. Schrefl and J. Fidler [159] have investigated the effect of different initial states on the initial magnetization curve of nanocrystalline permanent magnets. Namely, calculations for a-Fe/Nd2Fe14B and Fe3B/Nd2Fe14B composites [159] have showed that the thermally demagnetized state that stores a higher amount of exchange energy, leads to an increase of the initial susceptibility as compared to dc initial state. The a-Fe/Nd2Fe14B composite [159] has shown the improved saturation behavior that is attributed to the exchange field provided by a-Fe grains that already are oriented parallel to the field direction.

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