In this study, phase-field model is developed for ferroelectric/ferromagnetic nanocomposites, in which ferroelectric compositions is spatially varied along the thickness of ferroelectric layers. The developed phase field model is applied to investigate the effect of composition gradient on magnetoelectric response of the multilayer nanocomposite. Stripe domain structures are observed in both ferroelectric and ferromagnetic layers, however the sizes of magnetic domains are larger than that of polarization ones. Particularly, the size of polarization domains and geometry of domain walls are altered according to the gradient of ferroelectric compositions. The obtained results suggest that the larger the composition gradient is, the higher the magnetoelectric effect becomes. The enhancement of magnetoelectric effect is attributed to the concentration of energy in ferroelectric layer, which originates from the spatial variation of ferroelectric compositions.
Keyword
Magnetoelectric effect, ferroelectric/ferromagnetic nanocomposite, compositionally graded ferroelectric, phase-field model
