Comment on "High K Capacitors and OFET Gate Dielectrics from Self-Assembled BaTiO3 and (Ba,Sr) TiO3 Nanocrystals in the Superparaelectric Limit" - On the Superparaelectric State in BaTiO3 Nanocrystals

Size effects in ferroelectrics represent a largely debated subject, due to its high technological impact. Ferroelectricity is a cooperative long-range order phenomenon and deviations from bulk properties appear with size reduction. A progressive decrease of spontaneous polarization with decreasing size is predicted until a critical size, Rcr , corresponding to disappearance of ferroelectricity is attained. Other studies concluded that size effects are exclusively related to extrinsic phenomena or that ferroelectricity suppression originates from the increasing atomic positional disorder in spatiallyconfi ned systems.