Electric field control of magnetic susceptibility in laminate magnetostrictive/piezoelectric composites: Phase-field simulation and theoretical model

Electric field control of magnetic susceptibility in laminate magnetostrictive/piezoelectric composites promises to create a new class of magnetoelectric elements, voltage tunable inductors. To elucidate the underlying mechanism of electric field modulated magnetic susceptibility at the domain level, phase-field modeling, and computer simulation are employed to systematically study the laminate magnetoelectric composites of Terfenol-D and PZT, where polycrystalline Terfenol-D can provide a giant magnetoelectric coupling that is important for high-tunability voltage tunable inductors. The simulations focus on the interplay between magnetocrystalline anisotropy and stress-induced anisotropy that is induced by electric field and reveal three regimes of magnetic susceptibility behaviors: constant (regime I), fast-varying (regime II), and reciprocal linear (regime III), where regimes II and III can give rise to a high tunability. Such three regimes are attributed to different magnetization distribution and evolution mechanisms that are modulated by the stress-induced anisotropy. To further characterize the electric field control of magnetic susceptibility behaviors, a general theoretical model of laminate magnetoelectric (ME) composites based on polycrystalline magnetostrictive materials is developed, which reproduces the three regimes of susceptibility behaviors for polycrystalline Terfenol-D material. The general theoretical model for this specific system can also be extended to other laminate polycrystalline ME composites.