Non-Volatile Electric-Field Toggling Between Antiferromagnetic States

Magnetoelectric multiferroics are foreseen as paramount materials to control magnetism with an electric-field, targeting energy-efficient spintronics. The archetypal room-temperature antiferromagnetic ferroelectric, BiFeO3, harbors an incommensurate antiferromagnetic cycloid whose propagation direction is locked to ferroelectric domains. Epitaxial strain was shown to affect this antiferromagnetic ordering, stabilizing different cycloidal propagation directions, or a collinear antiferromagnetic state. Here we demonstrate the reversible, nonvolatile, electric-field triggered magnetic phase transition between two distinct antiferromagnetic states at room temperature. Using SrTiO3 vicinal substrates, we stabilize a single ferroelectric domain associated with a single antiferromagnetic cycloidal state in BiFeO3 epitaxial thin films. Electrically reversing the ferroelectric polarization deterministically within the same ferroelastic domain induces a reversible transition from a cycloidal to a collinear antiferromagnetic state, as directly visualized by scanning nitrogen vacancy (NV) magnetometry. These results bring insights into magnetoelectric devices for ultrafast and low-power spintronics.