Direct Observation of Ferroelectricity in Quasi‐Zero‐Dimensional Barium Titanate Nanoparticles

Practical difficulties in performing direct dielectric measurements have forced researchers to employ only indirect methods to study ferroelectricity in zero-dimensional materials; a clear understanding of this issue has thus remained elusive. Here, we directly confirm the existence of ferroelectricity in near-single BaTiO3 nanoparticles as small as 25 nm by using piezoresponse force microscopy (see figure), which verifies the theoretical predictions.