Noise in amorphous magnetic materials

Magnetic noises in rapidly quenched amorphous magnetic materials were examined. Magnetic noises are observed as the fluctuations of the induced voltage wave forms of the magnetic cores on every cycle of the alternating exciting field. Fe, Ni, and Co base alloys were tested, and the following results have been obtained. 1) CoFeSiB amorphous materials show the lowest noise, 2) Water quenching treatment decreased the noise remarkably, 3) The lower Curie temperature leads to the lower magnetic noise. 4) Some Co base amorphous alloys have the performance comparable to or better than that of the conventional polycrystalline material such as Supermalloy.