Non-volatile domain nucleation and growth in multiferroicBiFeO3 films

Abstract

We have presented a systematical study of the domain nucleation and growth behaviors in multiferroicBiFeO3 (BFO) films. Both the ferroelectric and the ferroelastic switching dynamics wereinvestigated. Several environmental parameters, including the polarization orientations, themonodomain-like matrix, and the ordered domain walls as local boundaries, were wellcontrolled by thin-film strain engineering through changing the vicinal anglesof the substrates. The tip-based domain dynamics was studied by subsequentpiezoresponse force microscope (PFM) imaging of the domain evolution underexternal voltage pulses. For the nanodomains written in the monodomain-likeenvironment, the domain wall performed the thermal activated motion. The as-grown71° domain walls can act as pinning centers for the ferroelectric domaingrowth driven by low fields; moreover, ferroelastic nucleation near a71° domain wall will cause the deformation of the domain wall. The ferroelastic domain growthpossessed relatively small activation fields, and therefore usually performed non-activatedmotion. This study revealed the effects of local environments on the dynamics formingnanoscale domains, and opened a pathway for applications in novel non-volatile functionaldevices.