Dependence of magnetostriction on induced anisotropy in metallic glasses

The dependence of engineering magnetostriction on induced anisotropy is investigated for an Fe₄₀Ni₄₀B₂₀ metallic glass. It is demonstrated that the degree of moment collinearity can be almost perfect after a suitable thermal treatment. A high magnitude for the induced anisotropy is not essential for good collinearity: rather it is essential that the anisotropy be sufficiently developed to produce a uniaxial character. It is possible for this alloy to find a field annealing regime where the degree of moment fanning is negligible, and hence to develop magnetostrictive strains close to the theoretical maximum. The maximum magnetostrictive strain which can be developed is independent of the magnitude of the induced anisotropy