Zero magnetostriction and extremely low residual magnetic loss in Fe-Co amorphous ribbons

The initial permeability μithe loss factor , and the inverse quality factor of Fe5Co70Si15B10ribbons 35μm, 30μm, 25μm and 21μm in thickness were measured with a Maxwell Bridge from room temperature to 140°C in the high-frequency region from 3kHz to 500kHz. The initial permeability of the ribbon 21μm in thickness was about 10,600 at 3kHz and 4300 at 500kHz. The residual loss coefficient C1and the hysteresis loss coefficient h1were extremely low, about and 60(cm/A), respectively. In the high-frequency region, the eddy current loss term increases with the square of the thickness of the ribbons and plays the most important part of all the magnetic losses.