Anisotropic magnetostriction for Tb_0.3Dy_0.7Fe_1.95 alloys under magnetomechanical loading

The anisotropic magnetostriction has been studied in detail for the positive magnetostrictive material of Terfenol-D under two types of magnetomechanical loading. Under the application of the axial compressive stress σ_∥ and the axial magnetic field H_∥, the axial negative magnetostriction was observed when H_∥ increased to coercive field around, which was similar with the butterfly hysteresis in PZT. However, under the application of the axial compressive stress σ_∥ and the transversal magnetic field H_⊥, the "W" shape magnetostriction was observed firstly, which should be taken into consideration to avoid unexpected accidents for practical applications. The anisotropic phenomenon was explained by the domain rotation mechanism, where the demagnetization field effect was considered due to the shape anisotropy of the materials.