Elastic properties of domains and domain walls in (K0.5Na0.5)NbO3 single crystal

The elastic properties of ferroelectric materials at the nanoscale are intricate, with domains and domain walls each having their own distinct elasticity – a property which can be exploited for tailoring materials performance. In this study, we report on the elastic response of the ferroelectric domain structure of a (K 0.5 Na 0.5 )NbO 3 single crystal, measured using an atomic force microscopy-based techniques. Before mapping the elastic properties, the domain structure was characterized using piezo-response force microscopy and transmission electron microscopy. The average measured reduced elastic modulus was ~130 GPa. The 90° domain walls exhibit a 20% difference in the reduces modulus, appearing elastically harder on one side of the domain and elastically softer of the other. In contrast, 60° domain walls showed no mechanical contrast with the neighboring domains. Anisotropy in elasticity was also observed between domains with different piezoelectric activity.