Dynamics of surface screening charges on domains of BiFeO3 films

Abstract

The dynamics of surface screening charges on BiFeO3 films with pre-written stripe domains was studied with surface potential measurements by Kelvin Probe Force Microscopy. The screening effect decays exponentially over time, and this decay is slower in the arrays with wider domains or larger intervals of domains, indicating that the in-plane diffusion of the surface screening charges plays a major role in the decay dynamics. The good agreement between experimental data and theoretical results based on diffusion-drift model confirms the mechanism of in-plane diffusion of the screening charges in the decay dynamics. Our work could provide a pathway to control the data stability of charge storage by artificially designing the ferroelectric domains.

Thickness-Dependent Domain Relaxation Dynamics Study in Epitaxial K0.5Na0.5NbO3 Ferroelectric Thin Films

“…Here, the self-polarization effect is excluded because if the self-polarization aligns as downward polarization and if positive voltage is applied through the tip, then the enhanced total electric field of the self-polarized region would give a better SP instead of a lesser value compared to that of the negative biased case . However, the surface charge effect is dominant for SP at ≈1 V bias in KNN thin films, whereas the polarization charge effect is dominant up to −3 V for the negative biased region and +1 V for the positive biased region in the case of PZT. , The time evolution of SP is closely related to the decay of the surface charges, which spread out of the written area via drift and diffusion process. , The dispersion of the surface charge follows exponential behavior. ,, Hence, the time evolution of SPs are fitted with the exponential relation where V r is the relaxed SP and τ is the decay constant.…”

“…7,20 The dispersion of the surface charge follows exponential behavior. 7,36,39 Hence, the time evolution of SPs are fitted with the exponential relation…”

Evolution of structural distortion in BiFeO3 thin films probed by second-harmonic generation

“…BiFeO 3 (BFO) has drawn considerable attention, since it has been found hitherto as the only single-phase room-temperature magnetoelectric multiferroic1234567. Meanwhile, tremendous activities have been engaged to study BFO thin films, which may meet the needs for microelectronic information storage devices89101112.…”