Magnetic properties of Fe-based bulk ferromagnetic glasses

Several Fe-based ferromagnetic bulk amorphous alloys, having compositions Fe61Co10Zr5W4B20; Fe61Co10Zr5W2Nb2B20; Fe61Co10 Zr2.5Hf2.5W2Nb2B20, have been prepared by suction casting, in the form of I mm diameter rods, and by melt spinning in the form of thick ribbons (thickness similar to 200 mu m). All these glasses have a large supercooled region T-x-T-g, ranging from 51 to 70 K, consistent with a large glass forming ability, that is promoted by the substantial differences in the atomic sizes of the constituent elements. We have obtained a saturation polarisation (mu M-0(S)) of similar to 0.8 T for Fe61Co10Zr5W4B20 and 0.9 T for Fe61Co10Zr5W2Nb2B20 and Fe61Co10Zr2.5Hf2.5W2Nb2B20, for both rod and ribbon forms. The coercivities of the samples range from.. 25 to 50 A/m, for ribbon and from 100 to 300 A/m for rods, when measured at 5 Hz. The coercivity is a parameter that is very sensitive to magnetic inhomogeneity and the data indicate some degree of such inhomogeneity in the samples, especially for the rods. Magnetoelastic resonance experiments were also performed, giving values of Young modulus of about 160 GPa, and magnetostriction coefficients of about 10(-5). (c) 2006 Published by Elsevier B.V.