Magnetic Annealing Effect of Amorphous (Fe1-xCox)77Si10B13 Alloys

The concentration dependence of the uniaxial magnetic anisotropy induced by magnetic annealing has been studied for rapidly quenched amorphous (Fe1-xCox)77Si10B13 (0≦x≦1) alloys by using a high sensitivity torque magnetometer. The induced uniaxial magnetic anisotropy constant was found to be a maximum, 8×103 erg/cm3, around x=0.5 and a minimum, 2×103 erg/cm3, at x=0 and 1. The result could not be explained either by the directional strain or by the directional alignment of impurities or vacancies. The concentration dependence of the uniaxial magnetic anisotropy induced really by magnetic annealing could be explained by the directional pair model of the clustering type proposed by Iwata.