Abstract Complex oxides provide an ideal playground for exploring the interplay among the fundamental degrees of freedom: structural (lattice), electronic (orbital and charge), and magnetic (spin). With trends toward device miniaturization, there is growing interest in combining electronic and magnetic properties into multifunctional thin-film materials for potential applications in novel versatile devices. Here, we report growth of ferromagnetic nanostructures on ferroelectric ( 1 − x )[Pb(Mg1/3Nb2/3)O3] − x[PbTiO3] (PMN-PT) single crystals. With careful control of material composition and application of electric field direction and amplitude, we realized stabilization of both monoclinic and orthorhombic phases in the PMN-PT single crystals with the intrinsic rhombohedral phase. Multistate magnetization modulation has been realized through phase transformation control in the ferroelectric component. This finding promises multistate information recording through magnetoelectric effect.