Interpretation of the magnetization mechanism in Terfenol-D using Barkhausen pulse-height analysis and irreversible magnetostriction

The ternary alloy Dy0.7Tb0.3Fe1.9, known as Terfenol-D, is a highly magnetostrictive alloy with magnetostriction coefficients along the principal crystallographic directions of λ111=1640×10−6 and λ100≤100(±30)×10−6. The bulk magnetostriction λ is dependent on the state of magnetization M, on the original domain configuration, and on the texture of the material. This paper reports on Barkhausen measurements and magnetostriction. The pulse-height distribution of Barkhausen emissions revealed events occurring at a specific amplitude which were stress dependent. The magnetostriction results gave a saturation magnetostriction in excess of 2000 μ strain.