Magnetostriction and dilatation measurements of Fe-Ni-Nb-B metallic glasses

Soft magnetic metallic glasses or their corresponding nanocrystalline counterparts based on Fe and on Ni frequently exhibit different magnetic properties. This work is devoted to rapidly quenched (Fe-Ni)81Nb7B12 ribbon system with the ratio of Ni/Fe being 0, 1/6, 1/3, 1/2, 1, 2 and 3 prepared by planar flow casting. Using temperature dependencies of dilatation, the Curie temperature TC and structural transitions (glass transition, crystallization) were determined. Direct measurement of magnetostriction was employed to determine the values of saturation magnetostriction λS at room temperature. The values for as-quenched samples with low Ni-content (0, 1/6) clearly indicate the proximity of TC to room temperature and thus the values of λS are low. The highest value of λS observed for Ni/Fe = 1/3 is 15.86 ppm. Increasing Ni-content leads to decrease of λS down to 1 ppm for Ni/Fe = 3, in accord with its negative value observed in pure Ni.