The magnetic properties of amorphous wires and their applications

Amorphous transition metal alloys with wire geometry have become available within the last ten years. The wires are produced by a somewhat different process to the chill-block melt spinning which is used to produce thin amorphous ribbons. The wire compositions of interest for magnetics have the general form (Fe,Co,Ni)SiB. The transition metal contents are in the range 70-80 atomic percent. In contrast to amorphous ribbons Si is a necessary component of the wire composition as it forms a very thin oxide layer on the molten alloy stream and prevents the stream breaking up. The magnetic properties of Fe_77.7Si_7.7B₁₅, (Fe_0.06Co _0.94)_72.5Si_12.5B₁₅ and Co _72.5Si_12.5B₁₅ compositions have attracted most attention because they exhibit positive, near-zero and negative magnetostriction respectively thus allowing the effect of magnetostriction on the magnetic properties to be investigated more rigorously