Persistent Ferroelectric Retention of Ferroelectric BiFeO₃ Thin Films

Ferroelectrics exhibiting robust and controllable polarization have attracted significant attention for next-generation memory technologies. However, these materials are often plagued by polarization relaxation within days to weeks. Here, we demonstrate exceptional long-term stability in as-grown mosaic-domain BiFeO3 thin films, showing virtually no measurable degradation in electro-writing nanodomains over 1 year (a >200 times improvement versus conventional uniform-domain ferroelectrics). Notably, scanning transmission electron microscopy and scanning probe microscopy reveal that the high-quality film achieves permanent polarization retention while preserving low operational voltage (5 V), half the voltage of previous ferroelectrics with comparable polarization retention. The thermodynamically balanced energy landscape of upward/downward polarization states within the mosaic domains stabilizes written domains without increasing the polarization switching activation field, dissolving the trade-off between energy efficiency and stability. These findings pave the pathway for high-density and low-energy-consumption ferroelectric memory and advanced multifunctional nanodevices.