Factors affecting core losses in oriented electrical steels at moderate inductions (invited)

Foster, K.; Littmann, M. F.

doi:doi:10.1063/1.334614

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Determination of variable magnetic anisotropy in sputtered Ni‐Fe films using hysteresis loops (abstract)

Hysteresis loops from Ni‐Fe films are known to take shapes that do not always resemble hard or easy axis loops. Distortions in the loops have earlier been related to the deposition conditions and thicknesses of the films. In this work a new experimental approach was developed to understand the nature of distortions in M‐H loops. Ni‐Fe films with 80 wt. % Ni were sputter deposited under different conditions to obtain varying amounts of easy [111] and hard [200] axis textures (producing variable m...

Effect of beam dwell time on surface changes during laser scribing

Laser scribing can be used to reduce the ferromagnetic domain size, and thus core loss, in grain‐oriented electrical steels. The localized stress required for domain‐size control can be produced either by shock deformation, optimally associated with beam dwell times (pulse lengths) less than 2×10−8 sec, or by thermal stressing occurring with dwell times optimally longer than 1×10−4 sec. In this paper we show that comparable core loss improvements can be obtained at greatly different dwell times,...

The effects of sheet thickness, orientation, grain size, silicon content, stress, domain control, and surface condition on core losses of both regular grain oriented (RGO) and high permeability (HGO) silicon steels in the induction range of 1.0 to 1.5 T were reviewed. Where possible, the effects of these factors were discussed in terms of total loss P_T hysteresis loss P_h eddy current loss P_e and eddy current loss anomaly factor η. The effect of decreasing sheet thickness t is dependent on P_e∼t, while for increased silicon content, P_e∼1/ρ. Improvements in orientation are shown mainly to decrease P_h, with the effect being larger at 1.5 T and above than at lower inductions. Grain size reductions, applied tensile stress, and other domain control methods are mainly aimed at reducing the 180° domain wall spacing 2L which in turn decreases η. Improved surface condition decreases both P_h and P_e, but mainly above 1.5 T.