DC and AC Characteristics of Co Base Amorphous Cores for Switching Applications

DC and AC magnetic characteristics with Co based non-magnetostrictive amorphous (FeCo)SiB, and (Fe(CoNi))SiB ribbons in which Co is partially substituted by Ni are studied in order to apply them to high frequency cores. It is shown that the substitution of Ni for Co decreases the coercive force. Hc also depends strongly upon the thickness of ribbons, and the ribbon core with 10 ¿m thick shows very low values of Hc which give an applicability of cores to the Switching Regulators drived at frequencies exceeding 100 kHz. The effects of the Samarium addition on the thermal stability are shown. The addition of Sm increases the crystallization temperature and the electric resistivity. But it lowers the magnetization.