Magnetization of glassy Co-B alloys

Abstract

By using a chill-casting technique, binary Co100−xBx alloys have been made for the boron content x between 10 and 31. The alloys with 14 ?x?29 are found to be noncrystalline, others being partially crystalline. The saturation magnetic moment per Co atom varies linearly from 1.49 μB at x=14 to 0.98 μB at x=29. At x=25, we find μs=1.09 μB which is close to μs=1.11 μB for the crystalline Co3B. The ferromagnetic Curie temperature, ϑf, is above the crystallization temperature of the material for x < 27 and is estimated to vary from about 780 K for x=22 to 670 K for x=29, giving a value of ϑf = 725 K for x=25. This value is close to ϑf = 747 K for the crystalline Co3B. Other evidence is given that the magnetic properties of glassy Co-B alloys differ very little from those of the crystalline counterparts, being quite different from the glassy Fe-B case reported previously.