Deterministic Memristive Polarization Switching in Relaxor Ferroelectrics

The burgeoning field of neuromorphic computing demands ferroelectric materials exhibiting memristive multilevel polarization to enable high-density memory storage and brain-inspired devices. Here, it is demonstrated deterministic multilevel polarization in a relaxor ferroelectric-rhombohedral PMN-PT through domain engineering, achieving precise control over stepwise domain switching. Using reciprocal space mapping (RSM) and in situ second-harmonic generation (SHG), it is shown that optimized electric pulses guide multi-domain switching to a 4R engineered domain state, stabilizing memristive behavior. In situ characterization techniques, including transmission electron microscopy and piezoelectric force microscopy, reveal that the memristive behavior arises from local domain rearrangements rather than crystal structure transitions. The resulting multilevel polarization states with up to 20 levels exhibit robust retention (>10⁴ s) and fatigue resistance (>10⁵ cycles) while maintaining high polarizability. Phase-field simulations corroborate these findings, offering microscopic insights into the repeatability of multilevel polarization. This approach overcomes the bistable limitations of conventional ferroelectrics, enabling stable multilevel polarization states that modulate mechanical, electrical, and optical properties. This results provide a versatile strategy for next-generation ferroelectric memristors, advancing neuromorphic and reconfigurable computing with minimal compromise in ferroelectric performance.