Low-Field Magnetostriction in an Annealed Co-30% Fe Alloy

Magnetostriction properties of a deformed and annealed Co-Fe alloy have been investigated. A significant magnetostriction value greater than ~110x10 sup (-6) was obtained in a cold-rolled and recrystallized sample at a practical, low field of ~ 100 Oe, while the as-cold-rolled sample gave a small magnetostriction of only ~15x10 sup (-6) for the same applied field. Cold-rolling and recrystallization produces much smaller magnetostriction in the longitudinal direction than the transverse direction in the low-field regime. The saturation magnetostriction of the recrystallized Co-Fe alloy was ~ 140x10 sup (-6). The drastic dependence of the magnetostriction behavior on the alloy processing is tentatively attributed to the microstructure and texture changes brought about by the heat treatment processing. The availability of such a high magnetostriction in low applied fields using a ductile and low-cost alloy material can be useful for various technical applications.