Effects Of Domain Wall Proximity On Nanoscale Polarization Switching In Relaxor-Ferroelectric Single Crystals

Domain walls' vibration and motion contribute significantly to the exceptionally large dielectric and piezoelectric response of ferroelectric materials. Yet, the specific length scales at which domain walls impact characteristic parameters remain largely unprobed. Previous studies examining correlation of domain wall proximity and functional response at the micrometer or submicrometer scales are often based on (locally or globally) "written" domains. The stability of such domains can be affected by many factors, resulting in convoluted effects of domain wall proximity and their stability when studying the local functional response. Herein, the effects of preexisting domain walls on the nanoscale polarization switching in a [001]-cut relaxor-ferroelectric 0.60Pb(Mg1/3Nb2/3)O3-0.40PbTiO3 single crystal are probed by piezoresponse force microscopy. It is found that domain wall proximity has limited impact on polarization switching for locations less than or similar to 300 nm away. While a transition from a growth- to nucleation-limited regime and/or change in dimensionality of domain growth is possibly observed, the effective impact on nucleation voltage does not exceed 25% variation. These results are consistent with the well-documented pervasive chemical, polar, and structural heterogeneities present in relaxor- ferroelectrics and the resulting "soft" piezoelectric behavior.