Composition Dependence of Induced Anisotropy in Cobalt-Based Amorphous Alloys Containing 4d and 5d Transition Metals

The induced anisotropy, Ki, was measured in cobalt-based amorphous alloys containing 4d and 5d transition metals. The value of Ki for (Co1-xTMx)0.9Zr0.1 (TM=Cr, Fe, Ni) alloys is much larger than that for metal-metalloid amorphous alloys, and shows a peak with increasing x. This behavior can be explained by the pair-ordering model, and the observed large Ki is attributed to strong pseudo-dipole interaction and weak non-magnetic interaction between magnetic atom pairs. Ki in (Co1-yZry)0.9B0.1 and Co1-yZr0.1MEy-0.1 (ME=Nb, Mo, W) alloys is also larger than that of metal-metalloid alloys, and decreases monotonically with increasing y. This decrease is closely related to the reduction of saturation magnetization, Ms, and the empirical low (Ki ∝Ms3.2) is obtained. These behaviors are also discussed in the framework of the pseudo-dipole interaction model.