A comparison of the power loss and domain structure of wide and narrow amorphous ribbons

The power loss of Metglas 2826 (Fe40Ni40P14B6) amorphous ribbons with two widths, namely 2 mm and 1.3 cm, has been measured over the range of frequency 20 to 1000 Hz at sinusoidal flux densities up to 0.75 T. Measurements have been made on both polished and unpolished samples since surface polishing was necessary to enable the observation of the domain Structures. The static unmagnetized domain structure has been observed to possess a high domain wall spacing. The power losses for the two sample widths are compared and it is seen that large differences occur, primarily in the excess eddy current component of the losses. It is also seen that the polishing procedure affects the losses markedly but the effect is inconsistent for each width, i.e. the polishing causes an increase in the loss of the 1.3 cm wide ribbon but reduces the loss of the narrow sample. It is shown that the effect of polishing is similar to the effect produced by a large tensile stress of the order of 25 MPa applied along the ribbon length for both widths of material.