Effect of demagnetization fields on the magnetization processes in Terfenol-D

Modeling of the magnetization processes in a twinned single crystal rod of Terfenol-D has been carried out under the principle of global energy minimization. The proposed model especially considers effects of the demagnetization fields, resulting from the accumulation of magnetic charges on the twin boundaries while the domain magnetization redistributes towards the direction of magnetic field applied along the rod axis [112], and includes other energies associated with magnetic anisotropy, magnetic field and applied stress. The results clearly illustrate the rapid burst change of strain at lower fields as well as the slow change in higher field ranges. The model also suggests that the demagnetization field hinders the magnetostriction along [112] reaching its maximum value in only one burst process. The predicted changes in the magnetization process are in good agreement with the experimental results. (C) 1999 Published by Elsevier Science B.V. All rights reserved.