Suppression of creep-regime dynamics in epitaxial ferroelectric BiFeO3 films

Abstract

Switching dynamics of ferroelectric materials are governed by the response of domain walls to applied electric field. In epitaxial ferroelectric films, thermally-activated &apos;creep&apos; motion plays a significant role in domain wall dynamics, and accordingly, detailed understanding of the system&apos;s switching properties requires that this creep motion be taken into account. Despite this importance, few studies have investigated creep motion in ferroelectric films under ac-driven force. Here, we explore ac hysteretic dynamics in epitaxial BiFeO<inf>3</inf> thin films, through ferroelectric hysteresis measurements, and stroboscopic piezoresponse force microscopy. We reveal that identically-fabricated BiFeO<inf>3</inf> films on SrRuO<inf>3</inf> or La<inf>0.67</inf>Sr<inf>0.33</inf>MnO<inf>3</inf> bottom electrodes exhibit markedly different switching behaviour, with BiFeO<inf>3</inf>/SrRuO<inf>3</inf> presenting essentially creep-free dynamics. This unprecedented result arises from the distinctive spatial inhomogeneities of the internal fields, these being influenced by the bottom electrode&apos;s surface morphology. Our findings further highlight the importance of controlling interface and defect characteristics, to engineer ferroelectric devices with optimised performance