The improved polarization retention through high-field charge injection in highly strained BiFeO ₃ thin films with preferred domain orientations

We transferred nanosecond ferroelectric domain switching currents of leaky Fe-enriched bismuth ferrite thin films into polarization-electric (P-E) hysteresis loops from which nanosecond-range polarization retention as well as imprint was extracted. All the films suffer from a quick remanent polarization loss after 4 s due to the appearance of a strong depolarization field arising from frozen compensation charges and large lattice-mismatching stresses. However, under an opposite field stressing the polarization enhances via near-electrode charge injection and approaches a theoretical value after 1000 μs, which supplies an effective way to symmetrize the P-E loop of a highly strained ferroelectric thin film.