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)(81)Nb7B12 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 T-C and structural transitions (glass transition, crystallization) were determined. Direct measurement of magnetostriction was employed to determine the values of saturation magnetostriction lambda(S) at room temperature. The values for as-quenched samples with low Ni-content (0, 1/6) clearly indicate the proximity of T-C to room temperature and thus the values of lambda(S) are low. The highest value of lambda(S) observed for Ni/Fe = 1/3 is 15.86 ppm. Increasing Ni-content leads to decrease of lambda(S) down to 1 ppm for Ni/Fe = 3, in accord with its negative value observed in pure Ni.