Rotational loss in thin gage soft magnetic materials

Rotational loss in several thin-gage ferromagnetic materials has been determined as a function of frequency and magnetization, using a rotating-sample method and sensing the perpendicular component of magnetization with a Hall effect element. Fe-base amorphous alloys have rotational losses at least a factor of ten lower than non-oriented Si-Fe at very low frequencies. Furthermore, the rotational loss in the thin high resistivity amorphous alloy is independent of frequency up to our present measurement limit of 80 Hz, while Si-Fe alloys show a significant increase in loss with increasing frequency. The rotational loss in planar oriented 6.5% Si-Fe is less than half that in the best non-oriented 3% Si-Fe.