Magnetomechanical coupling and permeability in transversely annealed metglas 2605 alloys

We have measured the magnetomechanical coupling factor, relative permeability, and magnetization as a function of annealing temperature and applied field in transversely annealed samples of Metglas 2605 CO (Fe67CO18B14Si1) and Metglas 2605 SC (Fe81B13.5Si3.5C2). In 2605 CO the maximum coupling factor of 0.71 was obtained for ribbons annealed between 360 and 375°C in fields greater than 1 k Oe. Plots of the impedance and admittance circles indicated a very low loss material. In samples with a coupling factor of 0.71, the Q value from the impedance circle was 35, while the Q value from the admittance circle was 120. In the 2605 SC alloy considerably higher coupling factors were calculated (0.9 to 0.96) due to the much lower anisotropy. The magnetization of the samples are mainly rotational in nature.