Unusual Behaviors of Electric-Field Control of Magnetism in Multiferroic Heterostructures via Multifactor Cooperation.

Electric-field control of magnetism (EFCM) is very important for the exploration of high-density, fast, and nonvolatile random-access memory with ultralow energy consumption. Here, we report the electric-field-induced ferroelectric phase transitions in Pb(Mg1/3Nb2/3)0.82Ti0.18O3 (PMN-0.18PT) and symmetry breaking of EFCM behaviors for corresponding directions in multiferroic heterostructures composed of amorphous ferromagnetic Co40Fe40B20 (CoFeB) and PMN-0.18PT. We uncover a new mechanism behind the unusual phenomena, involving coupling between CoFeB and PMN-0.18PT via complex cooperation of electric-field-induced ferroelectric phase transitions, competition of different ferroelectric domains, and internal electric field in PMN-0.18PT. The deterministic EFCM with reversible and nonvolatile nature opens up a new avenue for exploring EFCM in multiferroic heterostructures and is also significant for applications.