Unambiguous evidence of three coexisting ferroelectric phases in a lead-free LixNa1−xNbO3 system

We report here the presence of three coexisting ferroelectric phases in a lead-free lithium sodium niobate (Lix Na1−xNbO3; LNNx) system stable for 0.15≤x≤0.80, which contrasts the review report of Dixon and Lightfoot [Phys. Rev. B 97, 224105 (2018)]. More importantly, we have identified LNN20 as an important composition for technological applications due to its high dielectric permittivity, low loss, and high ferroelectric response. The anomalous dielectric and ferroelectric responses in LNN20 have been attributed to the morphotropic phase boundary like nature around this composition.