Effects of the addition of metalloids (P, Si, Ge) on the geometric and electronic structures and magnetic properties of Co-based amorphous alloys

Abstract

First-principles molecular dynamics was used to systematically investigate the effects of different metalloids on the soft magnetic properties of Co₇₅B_25-xM_x (M = P, Si, Ge; x = 5, 10, 15) amorphous alloys. The results reveal that with the substitution of B by P, Si, and Ge, the probability that Co atoms are situated in the vicinity of other Co atoms within amorphous alloys decreases, and the density of the amorphous alloys also tends to decrease. After 5 %–15 % of B is replaced by P, Si and Ge, the average magnetic moment of Co atoms in the amorphous alloy gradually decreases, and the simulation calculations agree well with the experimental results. As the quantity of nearest-neighbor Co atoms increases, the local magnetic moment of Co atoms gradually increases. In terms of electron gain and loss, the more charge Co atoms lose, the larger the magnetic moment of Co atoms.