New soft magnetic material with constant and adjustable permeability

New metallic magnetic ribbons with permeability of several hundreds and magnetic loss comparable to that of Mn-Zn ferrites were developed by crystallizing amorphous Fe-Cu-Nb-Si-B ribbons. Although the magnetic properties of as-annealed ribbons showed remarkable instability, they were stabilized by exposing the ribbon to large flux density before usage. The permeability of the stabilized ribbons could be adjusted to the desired value by controlling the flux density exposed for stabilization. The stabilized permeability was constant up to 400 kHz independent of the excited flux density, as long as the excited flux density did not exceed the flux density used for stabilization.